// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
 */
#include <linux/bpf.h>
#include <linux/bpf_trace.h>
#include <linux/bpf_lirc.h>
#include <linux/bpf_verifier.h>
#include <linux/btf.h>
#include <linux/syscalls.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include <linux/vmalloc.h>
#include <linux/mmzone.h>
#include <linux/anon_inodes.h>
#include <linux/fdtable.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/license.h>
#include <linux/filter.h>
#include <linux/version.h>
#include <linux/kernel.h>
#include <linux/idr.h>
#include <linux/cred.h>
#include <linux/timekeeping.h>
#include <linux/ctype.h>
#include <linux/nospec.h>
#include <linux/audit.h>
#include <uapi/linux/btf.h>
#include <linux/pgtable.h>
#include <linux/bpf_lsm.h>
#include <linux/poll.h>
#include <linux/bpf-netns.h>
#include <linux/rcupdate_trace.h>

#define IS_FD_ARRAY(map)                                                                                               \
    ((map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || (map)->map_type == BPF_MAP_TYPE_CGROUP_ARRAY ||               \
     (map)->map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS)
#define IS_FD_PROG_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PROG_ARRAY)
#define IS_FD_HASH(map) ((map)->map_type == BPF_MAP_TYPE_HASH_OF_MAPS)
#define IS_FD_MAP(map) (IS_FD_ARRAY(map) || IS_FD_PROG_ARRAY(map) || IS_FD_HASH(map))

#define BPF_OBJ_FLAG_MASK (BPF_F_RDONLY | BPF_F_WRONLY)

DEFINE_PER_CPU(int, bpf_prog_active);
static DEFINE_IDR(prog_idr);
static DEFINE_SPINLOCK(prog_idr_lock);
static DEFINE_IDR(map_idr);
static DEFINE_SPINLOCK(map_idr_lock);
static DEFINE_IDR(link_idr);
static DEFINE_SPINLOCK(link_idr_lock);

int sysctl_unprivileged_bpf_disabled __read_mostly = IS_BUILTIN(CONFIG_BPF_UNPRIV_DEFAULT_OFF) ? 2 : 0;

static const struct bpf_map_ops *const bpf_map_types[] = {
#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type)
#define BPF_MAP_TYPE(_id, _ops) [_id] = &(_ops),
#define BPF_LINK_TYPE(_id, _name)
#include <linux/bpf_types.h>
#undef BPF_PROG_TYPE
#undef BPF_MAP_TYPE
#undef BPF_LINK_TYPE
};

/*
 * If we're handed a bigger struct than we know of, ensure all the unknown bits
 * are 0 - i.e. new user-space does not rely on any kernel feature extensions
 * we don't know about yet.
 *
 * There is a ToCToU between this function call and the following
 * copy_from_user() call. However, this is not a concern since this function is
 * meant to be a future-proofing of bits.
 */
int bpf_check_uarg_tail_zero(void __user *uaddr, size_t expected_size, size_t actual_size)
{
    unsigned char __user *addr = uaddr + expected_size;
    int res;

    if (unlikely(actual_size > PAGE_SIZE)) { /* silly large */
        return -E2BIG;
    }

    if (actual_size <= expected_size) {
        return 0;
    }

    res = check_zeroed_user(addr, actual_size - expected_size);
    if (res < 0) {
        return res;
    }
    return res ? 0 : -E2BIG;
}

const struct bpf_map_ops bpf_map_offload_ops = {
    .map_meta_equal = bpf_map_meta_equal,
    .map_alloc = bpf_map_offload_map_alloc,
    .map_free = bpf_map_offload_map_free,
    .map_check_btf = map_check_no_btf,
};

static struct bpf_map *find_and_alloc_map(union bpf_attr *attr)
{
    const struct bpf_map_ops *ops;
    u32 type = attr->map_type;
    struct bpf_map *map;
    int err;

    if (type >= ARRAY_SIZE(bpf_map_types)) {
        return ERR_PTR(-EINVAL);
    }
    type = array_index_nospec(type, ARRAY_SIZE(bpf_map_types));
    ops = bpf_map_types[type];
    if (!ops) {
        return ERR_PTR(-EINVAL);
    }

    if (ops->map_alloc_check) {
        err = ops->map_alloc_check(attr);
        if (err) {
            return ERR_PTR(err);
        }
    }
    if (attr->map_ifindex) {
        ops = &bpf_map_offload_ops;
    }
    map = ops->map_alloc(attr);
    if (IS_ERR(map)) {
        return map;
    }
    map->ops = ops;
    map->map_type = type;
    return map;
}

static u32 bpf_map_value_size(struct bpf_map *map)
{
    if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
        map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY || map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) {
        return round_up(map->value_size, 0x8) * num_possible_cpus();
    } else if (IS_FD_MAP(map)) {
        return sizeof(u32);
    } else {
        return map->value_size;
    }
}

static void maybe_wait_bpf_programs(struct bpf_map *map)
{
    /* Wait for any running BPF programs to complete so that
     * userspace, when we return to it, knows that all programs
     * that could be running use the new map value.
     */
    if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS || map->map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS) {
        synchronize_rcu();
    }
}

static int bpf_map_update_value(struct bpf_map *map, struct fd f, void *key, void *value, __u64 flags)
{
    int err;

    /* Need to create a kthread, thus must support schedule */
    if (bpf_map_is_dev_bound(map)) {
        return bpf_map_offload_update_elem(map, key, value, flags);
    } else if (map->map_type == BPF_MAP_TYPE_CPUMAP || map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
        return map->ops->map_update_elem(map, key, value, flags);
    } else if (map->map_type == BPF_MAP_TYPE_SOCKHASH || map->map_type == BPF_MAP_TYPE_SOCKMAP) {
        return sock_map_update_elem_sys(map, key, value, flags);
    } else if (IS_FD_PROG_ARRAY(map)) {
        return bpf_fd_array_map_update_elem(map, f.file, key, value, flags);
    }

    bpf_disable_instrumentation();
    if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
        err = bpf_percpu_hash_update(map, key, value, flags);
    } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
        err = bpf_percpu_array_update(map, key, value, flags);
    } else if (map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) {
        err = bpf_percpu_cgroup_storage_update(map, key, value, flags);
    } else if (IS_FD_ARRAY(map)) {
        rcu_read_lock();
        err = bpf_fd_array_map_update_elem(map, f.file, key, value, flags);
        rcu_read_unlock();
    } else if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS) {
        rcu_read_lock();
        err = bpf_fd_htab_map_update_elem(map, f.file, key, value, flags);
        rcu_read_unlock();
    } else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) {
        /* rcu_read_lock() is not needed */
        err = bpf_fd_reuseport_array_update_elem(map, key, value, flags);
    } else if (map->map_type == BPF_MAP_TYPE_QUEUE || map->map_type == BPF_MAP_TYPE_STACK) {
        err = map->ops->map_push_elem(map, value, flags);
    } else {
        rcu_read_lock();
        err = map->ops->map_update_elem(map, key, value, flags);
        rcu_read_unlock();
    }
    bpf_enable_instrumentation();
    maybe_wait_bpf_programs(map);

    return err;
}

static int bpf_map_copy_value(struct bpf_map *map, void *key, void *value, __u64 flags)
{
    void *ptr;
    int err;

    if (bpf_map_is_dev_bound(map)) {
        return bpf_map_offload_lookup_elem(map, key, value);
    }

    bpf_disable_instrumentation();
    if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) {
        err = bpf_percpu_hash_copy(map, key, value);
    } else if (map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY) {
        err = bpf_percpu_array_copy(map, key, value);
    } else if (map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) {
        err = bpf_percpu_cgroup_storage_copy(map, key, value);
    } else if (map->map_type == BPF_MAP_TYPE_STACK_TRACE) {
        err = bpf_stackmap_copy(map, key, value);
    } else if (IS_FD_ARRAY(map) || IS_FD_PROG_ARRAY(map)) {
        err = bpf_fd_array_map_lookup_elem(map, key, value);
    } else if (IS_FD_HASH(map)) {
        err = bpf_fd_htab_map_lookup_elem(map, key, value);
    } else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) {
        err = bpf_fd_reuseport_array_lookup_elem(map, key, value);
    } else if (map->map_type == BPF_MAP_TYPE_QUEUE || map->map_type == BPF_MAP_TYPE_STACK) {
        err = map->ops->map_peek_elem(map, value);
    } else if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
        /* struct_ops map requires directly updating "value" */
        err = bpf_struct_ops_map_sys_lookup_elem(map, key, value);
    } else {
        rcu_read_lock();
        if (map->ops->map_lookup_elem_sys_only) {
            ptr = map->ops->map_lookup_elem_sys_only(map, key);
        } else {
            ptr = map->ops->map_lookup_elem(map, key);
        }
        if (IS_ERR(ptr)) {
            err = PTR_ERR(ptr);
        } else if (!ptr) {
            err = -ENOENT;
        } else {
            err = 0;
            if (flags & BPF_F_LOCK) {
                /* lock 'ptr' and copy everything but lock */
                copy_map_value_locked(map, value, ptr, true);
            } else {
                copy_map_value(map, value, ptr);
            }
            /* mask lock, since value wasn't zero inited */
            check_and_init_map_lock(map, value);
        }
        rcu_read_unlock();
    }

    bpf_enable_instrumentation();
    maybe_wait_bpf_programs(map);

    return err;
}

static void *_bpf_map_area_alloc(u64 size, int numa_node, bool mmapable)
{
    /* We really just want to fail instead of triggering OOM killer
     * under memory pressure, therefore we set __GFP_NORETRY to kmalloc,
     * which is used for lower order allocation requests.
     *
     * It has been observed that higher order allocation requests done by
     * vmalloc with __GFP_NORETRY being set might fail due to not trying
     * to reclaim memory from the page cache, thus we set
     * __GFP_RETRY_MAYFAIL to avoid such situations.
     */

    const gfp_t gfp = __GFP_NOWARN | __GFP_ZERO;
    unsigned int flags = 0;
    unsigned long align = 1;
    void *area;

    if (size >= SIZE_MAX) {
        return NULL;
    }

    /* kmalloc()'ed memory can't be mmap()'ed */
    if (mmapable) {
        BUG_ON(!PAGE_ALIGNED(size));
        align = SHMLBA;
        flags = VM_USERMAP;
    } else if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) {
        area = kmalloc_node(size, gfp | GFP_USER | __GFP_NORETRY, numa_node);
        if (area != NULL) {
            return area;
        }
    }

    return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END, gfp | GFP_KERNEL | __GFP_RETRY_MAYFAIL,
                                PAGE_KERNEL, flags, numa_node, __builtin_return_address(0));
}

void *bpf_map_area_alloc(u64 size, int numa_node)
{
    return _bpf_map_area_alloc(size, numa_node, false);
}

void *bpf_map_area_mmapable_alloc(u64 size, int numa_node)
{
    return _bpf_map_area_alloc(size, numa_node, true);
}

void bpf_map_area_free(void *area)
{
    kvfree(area);
}

static u32 bpf_map_flags_retain_permanent(u32 flags)
{
    /* Some map creation flags are not tied to the map object but
     * rather to the map fd instead, so they have no meaning upon
     * map object inspection since multiple file descriptors with
     * different (access) properties can exist here. Thus, given
     * this has zero meaning for the map itself, lets clear these
     * from here.
     */
    return flags & ~(BPF_F_RDONLY | BPF_F_WRONLY);
}

void bpf_map_init_from_attr(struct bpf_map *map, union bpf_attr *attr)
{
    map->map_type = attr->map_type;
    map->key_size = attr->key_size;
    map->value_size = attr->value_size;
    map->max_entries = attr->max_entries;
    map->map_flags = bpf_map_flags_retain_permanent(attr->map_flags);
    map->numa_node = bpf_map_attr_numa_node(attr);
}

static int bpf_charge_memlock(struct user_struct *user, u32 pages)
{
    unsigned long memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
    if (atomic_long_add_return(pages, &user->locked_vm) > memlock_limit) {
        atomic_long_sub(pages, &user->locked_vm);
        return -EPERM;
    }
    return 0;
}

static void bpf_uncharge_memlock(struct user_struct *user, u32 pages)
{
    if (user) {
        atomic_long_sub(pages, &user->locked_vm);
    }
}

int bpf_map_charge_init(struct bpf_map_memory *mem, u64 size)
{
    u32 pages = round_up(size, PAGE_SIZE) >> PAGE_SHIFT;
    struct user_struct *user;
    int ret;

    if (size >= U32_MAX - PAGE_SIZE) {
        return -E2BIG;
    }

    user = get_current_user();
    ret = bpf_charge_memlock(user, pages);
    if (ret) {
        free_uid(user);
        return ret;
    }

    mem->pages = pages;
    mem->user = user;

    return 0;
}

void bpf_map_charge_finish(struct bpf_map_memory *mem)
{
    bpf_uncharge_memlock(mem->user, mem->pages);
    free_uid(mem->user);
}

void bpf_map_charge_move(struct bpf_map_memory *dst, struct bpf_map_memory *src)
{
    *dst = *src;

    /* Make sure src will not be used for the redundant uncharging. */
    memset(src, 0, sizeof(struct bpf_map_memory));
}

int bpf_map_charge_memlock(struct bpf_map *map, u32 pages)
{
    int ret;

    ret = bpf_charge_memlock(map->memory.user, pages);
    if (ret) {
        return ret;
    }
    map->memory.pages += pages;
    return ret;
}

void bpf_map_uncharge_memlock(struct bpf_map *map, u32 pages)
{
    bpf_uncharge_memlock(map->memory.user, pages);
    map->memory.pages -= pages;
}

static int bpf_map_alloc_id(struct bpf_map *map)
{
    int id;

    idr_preload(GFP_KERNEL);
    spin_lock_bh(&map_idr_lock);
    id = idr_alloc_cyclic(&map_idr, map, 1, INT_MAX, GFP_ATOMIC);
    if (id > 0) {
        map->id = id;
    }
    spin_unlock_bh(&map_idr_lock);
    idr_preload_end();

    if (WARN_ON_ONCE(!id)) {
        return -ENOSPC;
    }

    return id > 0 ? 0 : id;
}

void bpf_map_free_id(struct bpf_map *map, bool do_idr_lock)
{
    unsigned long flags;

    /* Offloaded maps are removed from the IDR store when their device
     * disappears - even if someone holds an fd to them they are unusable,
     * the memory is gone, all ops will fail; they are simply waiting for
     * refcnt to drop to be freed.
     */
    if (!map->id) {
        return;
    }

    if (do_idr_lock) {
        spin_lock_irqsave(&map_idr_lock, flags);
    } else {
        __acquire(&map_idr_lock);
    }

    idr_remove(&map_idr, map->id);
    map->id = 0;

    if (do_idr_lock) {
        spin_unlock_irqrestore(&map_idr_lock, flags);
    } else {
        __release(&map_idr_lock);
    }
}

/* called from workqueue */
static void bpf_map_free_deferred(struct work_struct *work)
{
    struct bpf_map *map = container_of(work, struct bpf_map, work);
    struct bpf_map_memory mem;

    bpf_map_charge_move(&mem, &map->memory);
    security_bpf_map_free(map);
    /* implementation dependent freeing */
    map->ops->map_free(map);
    bpf_map_charge_finish(&mem);
}

static void bpf_map_put_uref(struct bpf_map *map)
{
    if (atomic64_dec_and_test(&map->usercnt)) {
        if (map->ops->map_release_uref) {
            map->ops->map_release_uref(map);
        }
    }
}

/* decrement map refcnt and schedule it for freeing via workqueue
 * (unrelying map implementation ops->map_free() might sleep)
 */
static void _bpf_map_put(struct bpf_map *map, bool do_idr_lock)
{
    if (atomic64_dec_and_test(&map->refcnt)) {
        /* bpf_map_free_id() must be called first */
        bpf_map_free_id(map, do_idr_lock);
        btf_put(map->btf);
        INIT_WORK(&map->work, bpf_map_free_deferred);
        schedule_work(&map->work);
    }
}

void bpf_map_put(struct bpf_map *map)
{
    _bpf_map_put(map, true);
}
EXPORT_SYMBOL_GPL(bpf_map_put);

void bpf_map_put_with_uref(struct bpf_map *map)
{
    bpf_map_put_uref(map);
    bpf_map_put(map);
}

static int bpf_map_release(struct inode *inode, struct file *filp)
{
    struct bpf_map *map = filp->private_data;

    if (map->ops->map_release) {
        map->ops->map_release(map, filp);
    }

    bpf_map_put_with_uref(map);
    return 0;
}

static fmode_t map_get_sys_perms(struct bpf_map *map, struct fd f)
{
    fmode_t mode = f.file->f_mode;

    /* Our file permissions may have been overridden by global
     * map permissions facing syscall side.
     */
    if (READ_ONCE(map->frozen)) {
        mode &= ~FMODE_CAN_WRITE;
    }
    return mode;
}

#ifdef CONFIG_PROC_FS
static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
{
    const struct bpf_map *map = filp->private_data;
    const struct bpf_array *array;
    u32 type = 0, jited = 0;

    if (map->map_type == BPF_MAP_TYPE_PROG_ARRAY) {
        array = container_of(map, struct bpf_array, map);
        spin_lock(&array->aux->owner.lock);
        type = array->aux->owner.type;
        jited = array->aux->owner.jited;
        spin_unlock(&array->aux->owner.lock);
    }

    seq_printf(m,
               "map_type:\t%u\n"
               "key_size:\t%u\n"
               "value_size:\t%u\n"
               "max_entries:\t%u\n"
               "map_flags:\t%#x\n"
               "memlock:\t%llu\n"
               "map_id:\t%u\n"
               "frozen:\t%u\n",
               map->map_type, map->key_size, map->value_size, map->max_entries, map->map_flags,
               map->memory.pages * 1ULL << PAGE_SHIFT, map->id, READ_ONCE(map->frozen));
    if (type) {
        seq_printf(m, "owner_prog_type:\t%u\n", type);
        seq_printf(m, "owner_jited:\t%u\n", jited);
    }
}
#endif

static ssize_t bpf_dummy_read(struct file *filp, char __user *buf, size_t siz, loff_t *ppos)
{
    /* We need this handler such that alloc_file() enables
     * f_mode with FMODE_CAN_READ.
     */
    return -EINVAL;
}

static ssize_t bpf_dummy_write(struct file *filp, const char __user *buf, size_t siz, loff_t *ppos)
{
    /* We need this handler such that alloc_file() enables
     * f_mode with FMODE_CAN_WRITE.
     */
    return -EINVAL;
}

/* called for any extra memory-mapped regions (except initial) */
static void bpf_map_mmap_open(struct vm_area_struct *vma)
{
    struct bpf_map *map = vma->vm_file->private_data;

    if (vma->vm_flags & VM_MAYWRITE) {
        mutex_lock(&map->freeze_mutex);
        map->writecnt++;
        mutex_unlock(&map->freeze_mutex);
    }
}

/* called for all unmapped memory region (including initial) */
static void bpf_map_mmap_close(struct vm_area_struct *vma)
{
    struct bpf_map *map = vma->vm_file->private_data;

    if (vma->vm_flags & VM_MAYWRITE) {
        mutex_lock(&map->freeze_mutex);
        map->writecnt--;
        mutex_unlock(&map->freeze_mutex);
    }
}

static const struct vm_operations_struct bpf_map_default_vmops = {
    .open = bpf_map_mmap_open,
    .close = bpf_map_mmap_close,
};

static int bpf_map_mmap(struct file *filp, struct vm_area_struct *vma)
{
    struct bpf_map *map = filp->private_data;
    int err;

    if (!map->ops->map_mmap || map_value_has_spin_lock(map)) {
        return -ENOTSUPP;
    }

    if (!(vma->vm_flags & VM_SHARED)) {
        return -EINVAL;
    }

    mutex_lock(&map->freeze_mutex);

    if (vma->vm_flags & VM_WRITE) {
        if (map->frozen) {
            err = -EPERM;
            goto out;
        }
        /* map is meant to be read-only, so do not allow mapping as
         * writable, because it's possible to leak a writable page
         * reference and allows user-space to still modify it after
         * freezing, while verifier will assume contents do not change
         */
        if (map->map_flags & BPF_F_RDONLY_PROG) {
            err = -EACCES;
            goto out;
        }
    }

    /* set default open/close callbacks */
    vma->vm_ops = &bpf_map_default_vmops;
    vma->vm_private_data = map;
    vma->vm_flags &= ~VM_MAYEXEC;
    if (!(vma->vm_flags & VM_WRITE)) {
        /* disallow re-mapping with PROT_WRITE */
        vma->vm_flags &= ~VM_MAYWRITE;
    }

    err = map->ops->map_mmap(map, vma);
    if (err) {
        goto out;
    }

    if (vma->vm_flags & VM_MAYWRITE) {
        map->writecnt++;
    }
out:
    mutex_unlock(&map->freeze_mutex);
    return err;
}

static __poll_t bpf_map_poll(struct file *filp, struct poll_table_struct *pts)
{
    struct bpf_map *map = filp->private_data;

    if (map->ops->map_poll) {
        return map->ops->map_poll(map, filp, pts);
    }

    return EPOLLERR;
}

const struct file_operations bpf_map_fops = {
#ifdef CONFIG_PROC_FS
    .show_fdinfo = bpf_map_show_fdinfo,
#endif
    .release = bpf_map_release,
    .read = bpf_dummy_read,
    .write = bpf_dummy_write,
    .mmap = bpf_map_mmap,
    .poll = bpf_map_poll,
};

int bpf_map_new_fd(struct bpf_map *map, int flags)
{
    int ret;

    ret = security_bpf_map(map, OPEN_FMODE(flags));
    if (ret < 0) {
        return ret;
    }

    return anon_inode_getfd("bpf-map", &bpf_map_fops, map, flags | O_CLOEXEC);
}

int bpf_get_file_flag(int flags)
{
    if ((flags & BPF_F_RDONLY) && (flags & BPF_F_WRONLY)) {
        return -EINVAL;
    }
    if (flags & BPF_F_RDONLY) {
        return O_RDONLY;
    }
    if (flags & BPF_F_WRONLY) {
        return O_WRONLY;
    }
    return O_RDWR;
}

/* helper macro to check that unused fields 'union bpf_attr' are zero */
#define CHECK_ATTR(CMD)                                                                                                \
    memchr_inv((void *)&attr->CMD##_LAST_FIELD + sizeof(attr->CMD##_LAST_FIELD), 0,                                    \
               sizeof(*attr) - offsetof(union bpf_attr, CMD##_LAST_FIELD) - sizeof(attr->CMD##_LAST_FIELD)) != NULL

/* dst and src must have at least "size" number of bytes.
 * Return strlen on success and < 0 on error.
 */
int bpf_obj_name_cpy(char *dst, const char *src, unsigned int size)
{
    const char *end = src + size;
    const char *orig_src = src;

    memset(dst, 0, size);
    /* Copy all isalnum(), '_' and '.' chars. */
    while (src < end && *src) {
        if (!isalnum(*src) && *src != '_' && *src != '.') {
            return -EINVAL;
        }
        *dst++ = *src++;
    }

    /* No '\0' found in "size" number of bytes */
    if (src == end) {
        return -EINVAL;
    }

    return src - orig_src;
}

int map_check_no_btf(const struct bpf_map *map, const struct btf *btf, const struct btf_type *key_type,
                     const struct btf_type *value_type)
{
    return -ENOTSUPP;
}

static int map_check_btf(struct bpf_map *map, const struct btf *btf, u32 btf_key_id, u32 btf_value_id)
{
    const struct btf_type *key_type, *value_type;
    u32 key_size, value_size;
    int ret = 0;

    /* Some maps allow key to be unspecified. */
    if (btf_key_id) {
        key_type = btf_type_id_size(btf, &btf_key_id, &key_size);
        if (!key_type || key_size != map->key_size) {
            return -EINVAL;
        }
    } else {
        key_type = btf_type_by_id(btf, 0);
        if (!map->ops->map_check_btf) {
            return -EINVAL;
        }
    }

    value_type = btf_type_id_size(btf, &btf_value_id, &value_size);
    if (!value_type || value_size != map->value_size) {
        return -EINVAL;
    }

    map->spin_lock_off = btf_find_spin_lock(btf, value_type);

    if (map_value_has_spin_lock(map)) {
        if (map->map_flags & BPF_F_RDONLY_PROG) {
            return -EACCES;
        }
        if (map->map_type != BPF_MAP_TYPE_HASH && map->map_type != BPF_MAP_TYPE_ARRAY &&
            map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE && map->map_type != BPF_MAP_TYPE_SK_STORAGE &&
            map->map_type != BPF_MAP_TYPE_INODE_STORAGE) {
            return -ENOTSUPP;
        }
        if (map->spin_lock_off + sizeof(struct bpf_spin_lock) > map->value_size) {
            WARN_ONCE(1, "verifier bug spin_lock_off %d value_size %d\n", map->spin_lock_off, map->value_size);
            return -EFAULT;
        }
    }

    if (map->ops->map_check_btf) {
        ret = map->ops->map_check_btf(map, btf, key_type, value_type);
    }

    return ret;
}

#define BPF_MAP_CREATE_LAST_FIELD btf_vmlinux_value_type_id
/* called via syscall */
static int map_create(union bpf_attr *attr)
{
    int numa_node = bpf_map_attr_numa_node(attr);
    struct bpf_map_memory mem;
    struct bpf_map *map;
    int f_flags;
    int err;

    err = CHECK_ATTR(BPF_MAP_CREATE);
    if (err) {
        return -EINVAL;
    }

    if (attr->btf_vmlinux_value_type_id) {
        if (attr->map_type != BPF_MAP_TYPE_STRUCT_OPS || attr->btf_key_type_id || attr->btf_value_type_id) {
            return -EINVAL;
        }
    } else if (attr->btf_key_type_id && !attr->btf_value_type_id) {
        return -EINVAL;
    }

    f_flags = bpf_get_file_flag(attr->map_flags);
    if (f_flags < 0) {
        return f_flags;
    }

    if (numa_node != NUMA_NO_NODE && ((unsigned int)numa_node >= nr_node_ids || !node_online(numa_node))) {
        return -EINVAL;
    }

    /* find map type and init map: hashtable vs rbtree vs bloom vs ... */
    map = find_and_alloc_map(attr);
    if (IS_ERR(map)) {
        return PTR_ERR(map);
    }

    err = bpf_obj_name_cpy(map->name, attr->map_name, sizeof(attr->map_name));
    if (err < 0) {
        goto free_map;
    }

    atomic64_set(&map->refcnt, 1);
    atomic64_set(&map->usercnt, 1);
    mutex_init(&map->freeze_mutex);

    map->spin_lock_off = -EINVAL;
    if (attr->btf_key_type_id || attr->btf_value_type_id ||
        /* Even the map's value is a kernel's struct,
         * the bpf_prog.o must have BTF to begin with
         * to figure out the corresponding kernel's
         * counter part.  Thus, attr->btf_fd has
         * to be valid also.
         */
        attr->btf_vmlinux_value_type_id) {
        struct btf *btf;

        btf = btf_get_by_fd(attr->btf_fd);
        if (IS_ERR(btf)) {
            err = PTR_ERR(btf);
            goto free_map;
        }
        map->btf = btf;

        if (attr->btf_value_type_id) {
            err = map_check_btf(map, btf, attr->btf_key_type_id, attr->btf_value_type_id);
            if (err) {
                goto free_map;
            }
        }

        map->btf_key_type_id = attr->btf_key_type_id;
        map->btf_value_type_id = attr->btf_value_type_id;
        map->btf_vmlinux_value_type_id = attr->btf_vmlinux_value_type_id;
    }

    err = security_bpf_map_alloc(map);
    if (err) {
        goto free_map;
    }

    err = bpf_map_alloc_id(map);
    if (err) {
        goto free_map_sec;
    }

    err = bpf_map_new_fd(map, f_flags);
    if (err < 0) {
        /* failed to allocate fd.
         * bpf_map_put_with_uref() is needed because the above
         * bpf_map_alloc_id() has published the map
         * to the userspace and the userspace may
         * have refcnt-ed it through BPF_MAP_GET_FD_BY_ID.
         */
        bpf_map_put_with_uref(map);
        return err;
    }

    return err;

free_map_sec:
    security_bpf_map_free(map);
free_map:
    btf_put(map->btf);
    bpf_map_charge_move(&mem, &map->memory);
    map->ops->map_free(map);
    bpf_map_charge_finish(&mem);
    return err;
}

/* if error is returned, fd is released.
 * On success caller should complete fd access with matching fdput()
 */
struct bpf_map *__bpf_map_get(struct fd f)
{
    if (!f.file) {
        return ERR_PTR(-EBADF);
    }
    if (f.file->f_op != &bpf_map_fops) {
        fdput(f);
        return ERR_PTR(-EINVAL);
    }

    return f.file->private_data;
}

void bpf_map_inc(struct bpf_map *map)
{
    atomic64_inc(&map->refcnt);
}
EXPORT_SYMBOL_GPL(bpf_map_inc);

void bpf_map_inc_with_uref(struct bpf_map *map)
{
    atomic64_inc(&map->refcnt);
    atomic64_inc(&map->usercnt);
}
EXPORT_SYMBOL_GPL(bpf_map_inc_with_uref);

struct bpf_map *bpf_map_get(u32 ufd)
{
    struct fd f = fdget(ufd);
    struct bpf_map *map;

    map = __bpf_map_get(f);
    if (IS_ERR(map)) {
        return map;
    }

    bpf_map_inc(map);
    fdput(f);

    return map;
}

struct bpf_map *bpf_map_get_with_uref(u32 ufd)
{
    struct fd f = fdget(ufd);
    struct bpf_map *map;

    map = __bpf_map_get(f);
    if (IS_ERR(map)) {
        return map;
    }

    bpf_map_inc_with_uref(map);
    fdput(f);

    return map;
}

/* map_idr_lock should have been held */
static struct bpf_map *_bpf_map_inc_not_zero(struct bpf_map *map, bool uref)
{
    int refold;

    refold = atomic64_fetch_add_unless(&map->refcnt, 1, 0);
    if (!refold) {
        return ERR_PTR(-ENOENT);
    }
    if (uref) {
        atomic64_inc(&map->usercnt);
    }

    return map;
}

struct bpf_map *bpf_map_inc_not_zero(struct bpf_map *map)
{
    spin_lock_bh(&map_idr_lock);
    map = _bpf_map_inc_not_zero(map, false);
    spin_unlock_bh(&map_idr_lock);

    return map;
}
EXPORT_SYMBOL_GPL(bpf_map_inc_not_zero);

int __weak bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)
{
    return -ENOTSUPP;
}

static void *__bpf_copy_key(void __user *ukey, u64 key_size)
{
    if (key_size) {
        return memdup_user(ukey, key_size);
    }

    if (ukey) {
        return ERR_PTR(-EINVAL);
    }

    return NULL;
}

/* last field in 'union bpf_attr' used by this command */
#define BPF_MAP_LOOKUP_ELEM_LAST_FIELD flags

static int map_lookup_elem(union bpf_attr *attr)
{
    void __user *ukey = u64_to_user_ptr(attr->key);
    void __user *uvalue = u64_to_user_ptr(attr->value);
    int ufd = attr->map_fd;
    struct bpf_map *map;
    void *key, *value;
    u32 value_size;
    struct fd f;
    int err;

    if (CHECK_ATTR(BPF_MAP_LOOKUP_ELEM)) {
        return -EINVAL;
    }

    if (attr->flags & ~BPF_F_LOCK) {
        return -EINVAL;
    }

    f = fdget(ufd);
    map = __bpf_map_get(f);
    if (IS_ERR(map)) {
        return PTR_ERR(map);
    }
    if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ)) {
        err = -EPERM;
        goto err_put;
    }

    if ((attr->flags & BPF_F_LOCK) && !map_value_has_spin_lock(map)) {
        err = -EINVAL;
        goto err_put;
    }

    key = __bpf_copy_key(ukey, map->key_size);
    if (IS_ERR(key)) {
        err = PTR_ERR(key);
        goto err_put;
    }

    value_size = bpf_map_value_size(map);

    err = -ENOMEM;
    value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
    if (!value) {
        goto free_key;
    }

    err = bpf_map_copy_value(map, key, value, attr->flags);
    if (err) {
        goto free_value;
    }

    err = -EFAULT;
    if (copy_to_user(uvalue, value, value_size) != 0) {
        goto free_value;
    }

    err = 0;

free_value:
    kfree(value);
free_key:
    kfree(key);
err_put:
    fdput(f);
    return err;
}

#define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags

static int map_update_elem(union bpf_attr *attr)
{
    void __user *ukey = u64_to_user_ptr(attr->key);
    void __user *uvalue = u64_to_user_ptr(attr->value);
    int ufd = attr->map_fd;
    struct bpf_map *map;
    void *key, *value;
    u32 value_size;
    struct fd f;
    int err;

    if (CHECK_ATTR(BPF_MAP_UPDATE_ELEM)) {
        return -EINVAL;
    }

    f = fdget(ufd);
    map = __bpf_map_get(f);
    if (IS_ERR(map)) {
        return PTR_ERR(map);
    }
    if (!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
        err = -EPERM;
        goto err_put;
    }

    if ((attr->flags & BPF_F_LOCK) && !map_value_has_spin_lock(map)) {
        err = -EINVAL;
        goto err_put;
    }

    key = __bpf_copy_key(ukey, map->key_size);
    if (IS_ERR(key)) {
        err = PTR_ERR(key);
        goto err_put;
    }

    if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
        map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY || map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE) {
        value_size = round_up(map->value_size, 0x8) * num_possible_cpus();
    } else {
        value_size = map->value_size;
    }

    err = -ENOMEM;
    value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
    if (!value) {
        goto free_key;
    }

    err = -EFAULT;
    if (copy_from_user(value, uvalue, value_size) != 0) {
        goto free_value;
    }

    err = bpf_map_update_value(map, f, key, value, attr->flags);

free_value:
    kfree(value);
free_key:
    kfree(key);
err_put:
    fdput(f);
    return err;
}

#define BPF_MAP_DELETE_ELEM_LAST_FIELD key

static int map_delete_elem(union bpf_attr *attr)
{
    void __user *ukey = u64_to_user_ptr(attr->key);
    int ufd = attr->map_fd;
    struct bpf_map *map;
    struct fd f;
    void *key;
    int err;

    if (CHECK_ATTR(BPF_MAP_DELETE_ELEM)) {
        return -EINVAL;
    }

    f = fdget(ufd);
    map = __bpf_map_get(f);
    if (IS_ERR(map)) {
        return PTR_ERR(map);
    }
    if (!(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
        err = -EPERM;
        goto err_put;
    }

    key = __bpf_copy_key(ukey, map->key_size);
    if (IS_ERR(key)) {
        err = PTR_ERR(key);
        goto err_put;
    }

    if (bpf_map_is_dev_bound(map)) {
        err = bpf_map_offload_delete_elem(map, key);
        goto out;
    } else if (IS_FD_PROG_ARRAY(map) || map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
        /* These maps require sleepable context */
        err = map->ops->map_delete_elem(map, key);
        goto out;
    }

    bpf_disable_instrumentation();
    rcu_read_lock();
    err = map->ops->map_delete_elem(map, key);
    rcu_read_unlock();
    bpf_enable_instrumentation();
    maybe_wait_bpf_programs(map);
out:
    kfree(key);
err_put:
    fdput(f);
    return err;
}

/* last field in 'union bpf_attr' used by this command */
#define BPF_MAP_GET_NEXT_KEY_LAST_FIELD next_key

static int map_get_next_key(union bpf_attr *attr)
{
    void __user *ukey = u64_to_user_ptr(attr->key);
    void __user *unext_key = u64_to_user_ptr(attr->next_key);
    int ufd = attr->map_fd;
    struct bpf_map *map;
    void *key, *next_key;
    struct fd f;
    int err;

    if (CHECK_ATTR(BPF_MAP_GET_NEXT_KEY)) {
        return -EINVAL;
    }

    f = fdget(ufd);
    map = __bpf_map_get(f);
    if (IS_ERR(map)) {
        return PTR_ERR(map);
    }
    if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ)) {
        err = -EPERM;
        goto err_put;
    }

    if (ukey) {
        key = __bpf_copy_key(ukey, map->key_size);
        if (IS_ERR(key)) {
            err = PTR_ERR(key);
            goto err_put;
        }
    } else {
        key = NULL;
    }

    err = -ENOMEM;
    next_key = kmalloc(map->key_size, GFP_USER);
    if (!next_key) {
        goto free_key;
    }

    if (bpf_map_is_dev_bound(map)) {
        err = bpf_map_offload_get_next_key(map, key, next_key);
        goto out;
    }

    rcu_read_lock();
    err = map->ops->map_get_next_key(map, key, next_key);
    rcu_read_unlock();
out:
    if (err) {
        goto free_next_key;
    }

    err = -EFAULT;
    if (copy_to_user(unext_key, next_key, map->key_size) != 0) {
        goto free_next_key;
    }

    err = 0;

free_next_key:
    kfree(next_key);
free_key:
    kfree(key);
err_put:
    fdput(f);
    return err;
}

int generic_map_delete_batch(struct bpf_map *map, const union bpf_attr *attr, union bpf_attr __user *uattr)
{
    void __user *keys = u64_to_user_ptr(attr->batch.keys);
    u32 cp, max_count;
    int err = 0;
    void *key;

    if (attr->batch.elem_flags & ~BPF_F_LOCK) {
        return -EINVAL;
    }

    if ((attr->batch.elem_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map)) {
        return -EINVAL;
    }

    max_count = attr->batch.count;
    if (!max_count) {
        return 0;
    }

    key = kmalloc(map->key_size, GFP_USER | __GFP_NOWARN);
    if (!key) {
        return -ENOMEM;
    }

    for (cp = 0; cp < max_count; cp++) {
        err = -EFAULT;
        if (copy_from_user(key, keys + cp * map->key_size, map->key_size)) {
            break;
        }

        if (bpf_map_is_dev_bound(map)) {
            err = bpf_map_offload_delete_elem(map, key);
            break;
        }

        bpf_disable_instrumentation();
        rcu_read_lock();
        err = map->ops->map_delete_elem(map, key);
        rcu_read_unlock();
        bpf_enable_instrumentation();
        maybe_wait_bpf_programs(map);
        if (err) {
            break;
        }
    }
    if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp))) {
        err = -EFAULT;
    }

    kfree(key);
    return err;
}

int generic_map_update_batch(struct bpf_map *map, const union bpf_attr *attr, union bpf_attr __user *uattr)
{
    void __user *values = u64_to_user_ptr(attr->batch.values);
    void __user *keys = u64_to_user_ptr(attr->batch.keys);
    u32 value_size, cp, max_count;
    int ufd = attr->batch.map_fd;
    void *key, *value;
    struct fd f;
    int err = 0;

    if (attr->batch.elem_flags & ~BPF_F_LOCK) {
        return -EINVAL;
    }

    if ((attr->batch.elem_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map)) {
        return -EINVAL;
    }

    value_size = bpf_map_value_size(map);

    max_count = attr->batch.count;
    if (!max_count) {
        return 0;
    }

    key = kmalloc(map->key_size, GFP_USER | __GFP_NOWARN);
    if (!key) {
        return -ENOMEM;
    }

    value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
    if (!value) {
        kfree(key);
        return -ENOMEM;
    }

    f = fdget(ufd); /* bpf_map_do_batch() guarantees ufd is valid */
    for (cp = 0; cp < max_count; cp++) {
        err = -EFAULT;
        if (copy_from_user(key, keys + cp * map->key_size, map->key_size) ||
            copy_from_user(value, values + cp * value_size, value_size)) {
            break;
        }

        err = bpf_map_update_value(map, f, key, value, attr->batch.elem_flags);

        if (err) {
            break;
        cond_resched();
        }
    }

    if (copy_to_user(&uattr->batch.count, &cp, sizeof(cp))) {
        err = -EFAULT;
    }

    kfree(value);
    kfree(key);
    fdput(f);
    return err;
}

#define MAP_LOOKUP_RETRIES 3

int generic_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr, union bpf_attr __user *uattr)
{
    void __user *uobatch = u64_to_user_ptr(attr->batch.out_batch);
    void __user *ubatch = u64_to_user_ptr(attr->batch.in_batch);
    void __user *values = u64_to_user_ptr(attr->batch.values);
    void __user *keys = u64_to_user_ptr(attr->batch.keys);
    void *buf, *buf_prevkey, *prev_key, *key, *value;
    int err, retry = MAP_LOOKUP_RETRIES;
    u32 value_size, cp, max_count;

    if (attr->batch.elem_flags & ~BPF_F_LOCK) {
        return -EINVAL;
    }

    if ((attr->batch.elem_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map)) {
        return -EINVAL;
    }

    value_size = bpf_map_value_size(map);

    max_count = attr->batch.count;
    if (!max_count) {
        return 0;
    }

    if (put_user(0, &uattr->batch.count)) {
        return -EFAULT;
    }

    buf_prevkey = kmalloc(map->key_size, GFP_USER | __GFP_NOWARN);
    if (!buf_prevkey) {
        return -ENOMEM;
    }

    buf = kmalloc(map->key_size + value_size, GFP_USER | __GFP_NOWARN);
    if (!buf) {
        kfree(buf_prevkey);
        return -ENOMEM;
    }

    err = -EFAULT;
    prev_key = NULL;
    if (ubatch && copy_from_user(buf_prevkey, ubatch, map->key_size)) {
        goto free_buf;
    }
    key = buf;
    value = key + map->key_size;
    if (ubatch) {
        prev_key = buf_prevkey;
    }

    for (cp = 0; cp < max_count;) {
        rcu_read_lock();
        err = map->ops->map_get_next_key(map, prev_key, key);
        rcu_read_unlock();
        if (err) {
            break;
        }
        err = bpf_map_copy_value(map, key, value, attr->batch.elem_flags);

        if (err == -ENOENT) {
            if (retry) {
                retry--;
                continue;
            }
            err = -EINTR;
            break;
        }

        if (err) {
            goto free_buf;
        }

        if (copy_to_user(keys + cp * map->key_size, key, map->key_size)) {
            err = -EFAULT;
            goto free_buf;
        }
        if (copy_to_user(values + cp * value_size, value, value_size)) {
            err = -EFAULT;
            goto free_buf;
        }

        if (!prev_key) {
            prev_key = buf_prevkey;
        }

        swap(prev_key, key);
        retry = MAP_LOOKUP_RETRIES;
        cp++;
        cond_resched();
    }

    if (err == -EFAULT) {
        goto free_buf;
    }

    if ((copy_to_user(&uattr->batch.count, &cp, sizeof(cp)) ||
         (cp && copy_to_user(uobatch, prev_key, map->key_size)))) {
        err = -EFAULT;
    }

free_buf:
    kfree(buf_prevkey);
    kfree(buf);
    return err;
}

#define BPF_MAP_LOOKUP_AND_DELETE_ELEM_LAST_FIELD value

static int map_lookup_and_delete_elem(union bpf_attr *attr)
{
    void __user *ukey = u64_to_user_ptr(attr->key);
    void __user *uvalue = u64_to_user_ptr(attr->value);
    int ufd = attr->map_fd;
    struct bpf_map *map;
    void *key, *value;
    u32 value_size;
    struct fd f;
    int err;

    if (CHECK_ATTR(BPF_MAP_LOOKUP_AND_DELETE_ELEM)) {
        return -EINVAL;
    }

    f = fdget(ufd);
    map = __bpf_map_get(f);
    if (IS_ERR(map)) {
        return PTR_ERR(map);
    }
    if (!(map_get_sys_perms(map, f) & FMODE_CAN_READ) || !(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
        err = -EPERM;
        goto err_put;
    }

    key = __bpf_copy_key(ukey, map->key_size);
    if (IS_ERR(key)) {
        err = PTR_ERR(key);
        goto err_put;
    }

    value_size = map->value_size;

    err = -ENOMEM;
    value = kmalloc(value_size, GFP_USER | __GFP_NOWARN);
    if (!value) {
        goto free_key;
    }

    if (map->map_type == BPF_MAP_TYPE_QUEUE || map->map_type == BPF_MAP_TYPE_STACK) {
        err = map->ops->map_pop_elem(map, value);
    } else {
        err = -ENOTSUPP;
    }

    if (err) {
        goto free_value;
    }

    if (copy_to_user(uvalue, value, value_size) != 0) {
        err = -EFAULT;
        goto free_value;
    }

    err = 0;

free_value:
    kfree(value);
free_key:
    kfree(key);
err_put:
    fdput(f);
    return err;
}

#define BPF_MAP_FREEZE_LAST_FIELD map_fd

static int map_freeze(const union bpf_attr *attr)
{
    int err = 0, ufd = attr->map_fd;
    struct bpf_map *map;
    struct fd f;

    if (CHECK_ATTR(BPF_MAP_FREEZE)) {
        return -EINVAL;
    }

    f = fdget(ufd);
    map = __bpf_map_get(f);
    if (IS_ERR(map)) {
        return PTR_ERR(map);
    }

    if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
        fdput(f);
        return -ENOTSUPP;
    }

    mutex_lock(&map->freeze_mutex);

    if (map->writecnt) {
        err = -EBUSY;
        goto err_put;
    }
    if (READ_ONCE(map->frozen)) {
        err = -EBUSY;
        goto err_put;
    }
    if (!bpf_capable()) {
        err = -EPERM;
        goto err_put;
    }

    WRITE_ONCE(map->frozen, true);
err_put:
    mutex_unlock(&map->freeze_mutex);
    fdput(f);
    return err;
}

static const struct bpf_prog_ops *const bpf_prog_types[] = {
#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) [_id] = &_name##_prog_ops,
#define BPF_MAP_TYPE(_id, _ops)
#define BPF_LINK_TYPE(_id, _name)
#include <linux/bpf_types.h>
#undef BPF_PROG_TYPE
#undef BPF_MAP_TYPE
#undef BPF_LINK_TYPE
};

static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog)
{
    const struct bpf_prog_ops *ops;

    if (type >= ARRAY_SIZE(bpf_prog_types)) {
        return -EINVAL;
    }
    type = array_index_nospec(type, ARRAY_SIZE(bpf_prog_types));
    ops = bpf_prog_types[type];
    if (!ops) {
        return -EINVAL;
    }

    if (!bpf_prog_is_dev_bound(prog->aux)) {
        prog->aux->ops = ops;
    } else {
        prog->aux->ops = &bpf_offload_prog_ops;
    }
    prog->type = type;
    return 0;
}

enum bpf_audit {
    BPF_AUDIT_LOAD,
    BPF_AUDIT_UNLOAD,
    BPF_AUDIT_MAX,
};

static const char *const bpf_audit_str[BPF_AUDIT_MAX] = {
    [BPF_AUDIT_LOAD] = "LOAD",
    [BPF_AUDIT_UNLOAD] = "UNLOAD",
};

static void bpf_audit_prog(const struct bpf_prog *prog, unsigned int op)
{
    struct audit_context *ctx = NULL;
    struct audit_buffer *ab;

    if (WARN_ON_ONCE(op >= BPF_AUDIT_MAX)) {
        return;
    }
    if (audit_enabled == AUDIT_OFF) {
        return;
    }
    if (op == BPF_AUDIT_LOAD) {
        ctx = audit_context();
    }
    ab = audit_log_start(ctx, GFP_ATOMIC, AUDIT_BPF);
    if (unlikely(!ab)) {
        return;
    }
    audit_log_format(ab, "prog-id=%u op=%s", prog->aux->id, bpf_audit_str[op]);
    audit_log_end(ab);
}

int __bpf_prog_charge(struct user_struct *user, u32 pages)
{
    unsigned long memlock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
    unsigned long user_bufs;

    if (user) {
        user_bufs = atomic_long_add_return(pages, &user->locked_vm);
        if (user_bufs > memlock_limit) {
            atomic_long_sub(pages, &user->locked_vm);
            return -EPERM;
        }
    }

    return 0;
}

void __bpf_prog_uncharge(struct user_struct *user, u32 pages)
{
    if (user) {
        atomic_long_sub(pages, &user->locked_vm);
    }
}

static int bpf_prog_charge_memlock(struct bpf_prog *prog)
{
    struct user_struct *user = get_current_user();
    int ret;

    ret = __bpf_prog_charge(user, prog->pages);
    if (ret) {
        free_uid(user);
        return ret;
    }

    prog->aux->user = user;
    return 0;
}

static void bpf_prog_uncharge_memlock(struct bpf_prog *prog)
{
    struct user_struct *user = prog->aux->user;

    __bpf_prog_uncharge(user, prog->pages);
    free_uid(user);
}

static int bpf_prog_alloc_id(struct bpf_prog *prog)
{
    int id;

    idr_preload(GFP_KERNEL);
    spin_lock_bh(&prog_idr_lock);
    id = idr_alloc_cyclic(&prog_idr, prog, 1, INT_MAX, GFP_ATOMIC);
    if (id > 0) {
        prog->aux->id = id;
    }
    spin_unlock_bh(&prog_idr_lock);
    idr_preload_end();

    /* id is in [1, INT_MAX) */
    if (WARN_ON_ONCE(!id)) {
        return -ENOSPC;
    }

    return id > 0 ? 0 : id;
}

void bpf_prog_free_id(struct bpf_prog *prog, bool do_idr_lock)
{
    /* cBPF to eBPF migrations are currently not in the idr store.
     * Offloaded programs are removed from the store when their device
     * disappears - even if someone grabs an fd to them they are unusable,
     * simply waiting for refcnt to drop to be freed.
     */
    if (!prog->aux->id) {
        return;
    }

    if (do_idr_lock) {
        spin_lock_bh(&prog_idr_lock);
    } else {
        __acquire(&prog_idr_lock);
    }

    idr_remove(&prog_idr, prog->aux->id);
    prog->aux->id = 0;

    if (do_idr_lock) {
        spin_unlock_bh(&prog_idr_lock);
    } else {
        __release(&prog_idr_lock);
    }
}

static void _bpf_prog_put_rcu(struct rcu_head *rcu)
{
    struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu);

    kvfree(aux->func_info);
    kfree(aux->func_info_aux);
    bpf_prog_uncharge_memlock(aux->prog);
    security_bpf_prog_free(aux);
    bpf_prog_free(aux->prog);
}

static void _bpf_prog_put_noref(struct bpf_prog *prog, bool deferred)
{
    bpf_prog_kallsyms_del_all(prog);
    btf_put(prog->aux->btf);
    bpf_prog_free_linfo(prog);

    if (deferred) {
        if (prog->aux->sleepable) {
            call_rcu_tasks_trace(&prog->aux->rcu, _bpf_prog_put_rcu);
        } else {
            call_rcu(&prog->aux->rcu, _bpf_prog_put_rcu);
        }
    } else {
        _bpf_prog_put_rcu(&prog->aux->rcu);
    }
}

static void _bpf_prog_put(struct bpf_prog *prog, bool do_idr_lock)
{
    if (atomic64_dec_and_test(&prog->aux->refcnt)) {
        perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_UNLOAD, 0);
        bpf_audit_prog(prog, BPF_AUDIT_UNLOAD);
        /* bpf_prog_free_id() must be called first */
        bpf_prog_free_id(prog, do_idr_lock);
        _bpf_prog_put_noref(prog, true);
    }
}

void bpf_prog_put(struct bpf_prog *prog)
{
    _bpf_prog_put(prog, true);
}
EXPORT_SYMBOL_GPL(bpf_prog_put);

static int bpf_prog_release(struct inode *inode, struct file *filp)
{
    struct bpf_prog *prog = filp->private_data;

    bpf_prog_put(prog);
    return 0;
}

static void bpf_prog_get_stats(const struct bpf_prog *prog, struct bpf_prog_stats *stats)
{
    u64 nsecs = 0, cnt = 0;
    int cpu;

    for_each_possible_cpu(cpu)
    {
        const struct bpf_prog_stats *st;
        unsigned int start;
        u64 tnsecs, tcnt;

        st = per_cpu_ptr(prog->aux->stats, cpu);
        do {
            start = u64_stats_fetch_begin_irq(&st->syncp);
            tnsecs = st->nsecs;
            tcnt = st->cnt;
        } while (u64_stats_fetch_retry_irq(&st->syncp, start));
        nsecs += tnsecs;
        cnt += tcnt;
    }
    stats->nsecs = nsecs;
    stats->cnt = cnt;
}

#ifdef CONFIG_PROC_FS
static void bpf_prog_show_fdinfo(struct seq_file *m, struct file *filp)
{
    const struct bpf_prog *prog = filp->private_data;
    char prog_tag[sizeof(prog->tag) * 0x2 + 1] = {};
    struct bpf_prog_stats stats;

    bpf_prog_get_stats(prog, &stats);
    bin2hex(prog_tag, prog->tag, sizeof(prog->tag));
    seq_printf(m,
               "prog_type:\t%u\n"
               "prog_jited:\t%u\n"
               "prog_tag:\t%s\n"
               "memlock:\t%llu\n"
               "prog_id:\t%u\n"
               "run_time_ns:\t%llu\n"
               "run_cnt:\t%llu\n",
               prog->type, prog->jited, prog_tag, prog->pages * 1ULL << PAGE_SHIFT, prog->aux->id, stats.nsecs,
               stats.cnt);
}
#endif

const struct file_operations bpf_prog_fops = {
#ifdef CONFIG_PROC_FS
    .show_fdinfo = bpf_prog_show_fdinfo,
#endif
    .release = bpf_prog_release,
    .read = bpf_dummy_read,
    .write = bpf_dummy_write,
};

int bpf_prog_new_fd(struct bpf_prog *prog)
{
    int ret;

    ret = security_bpf_prog(prog);
    if (ret < 0) {
        return ret;
    }

    return anon_inode_getfd("bpf-prog", &bpf_prog_fops, prog, O_RDWR | O_CLOEXEC);
}

static struct bpf_prog *i_bpf_prog_get(struct fd f)
{
    if (!f.file) {
        return ERR_PTR(-EBADF);
    }
    if (f.file->f_op != &bpf_prog_fops) {
        fdput(f);
        return ERR_PTR(-EINVAL);
    }

    return f.file->private_data;
}

void bpf_prog_add(struct bpf_prog *prog, int i)
{
    atomic64_add(i, &prog->aux->refcnt);
}
EXPORT_SYMBOL_GPL(bpf_prog_add);

void bpf_prog_sub(struct bpf_prog *prog, int i)
{
    /* Only to be used for undoing previous bpf_prog_add() in some
     * error path. We still know that another entity in our call
     * path holds a reference to the program, thus atomic_sub() can
     * be safely used in such cases!
     */
    WARN_ON(atomic64_sub_return(i, &prog->aux->refcnt) == 0);
}
EXPORT_SYMBOL_GPL(bpf_prog_sub);

void bpf_prog_inc(struct bpf_prog *prog)
{
    atomic64_inc(&prog->aux->refcnt);
}
EXPORT_SYMBOL_GPL(bpf_prog_inc);

/* prog_idr_lock should have been held */
struct bpf_prog *bpf_prog_inc_not_zero(struct bpf_prog *prog)
{
    int refold;

    refold = atomic64_fetch_add_unless(&prog->aux->refcnt, 1, 0);
    if (!refold) {
        return ERR_PTR(-ENOENT);
    }

    return prog;
}
EXPORT_SYMBOL_GPL(bpf_prog_inc_not_zero);

bool bpf_prog_get_ok(struct bpf_prog *prog, enum bpf_prog_type *attach_type, bool attach_drv)
{
    /* not an attachment, just a refcount inc, always allow */
    if (!attach_type) {
        return true;
    }

    if (prog->type != *attach_type) {
        return false;
    }
    if (bpf_prog_is_dev_bound(prog->aux) && !attach_drv) {
        return false;
    }

    return true;
}

static struct bpf_prog *_bpf_prog_get(u32 ufd, enum bpf_prog_type *attach_type, bool attach_drv)
{
    struct fd f = fdget(ufd);
    struct bpf_prog *prog;

    prog = i_bpf_prog_get(f);
    if (IS_ERR(prog)) {
        return prog;
    }
    if (!bpf_prog_get_ok(prog, attach_type, attach_drv)) {
        prog = ERR_PTR(-EINVAL);
        goto out;
    }

    bpf_prog_inc(prog);
out:
    fdput(f);
    return prog;
}

struct bpf_prog *bpf_prog_get(u32 ufd)
{
    return _bpf_prog_get(ufd, NULL, false);
}

struct bpf_prog *bpf_prog_get_type_dev(u32 ufd, enum bpf_prog_type type, bool attach_drv)
{
    return _bpf_prog_get(ufd, &type, attach_drv);
}
EXPORT_SYMBOL_GPL(bpf_prog_get_type_dev);

/* Initially all BPF programs could be loaded w/o specifying
 * expected_attach_type. Later for some of them specifying expected_attach_type
 * at load time became required so that program could be validated properly.
 * Programs of types that are allowed to be loaded both w/ and w/o (for
 * backward compatibility) expected_attach_type, should have the default attach
 * type assigned to expected_attach_type for the latter case, so that it can be
 * validated later at attach time.
 *
 * bpf_prog_load_fixup_attach_type() sets expected_attach_type in @attr if
 * prog type requires it but has some attach types that have to be backward
 * compatible.
 */
static void bpf_prog_load_fixup_attach_type(union bpf_attr *attr)
{
    if (attr->prog_type == BPF_PROG_TYPE_CGROUP_SOCK) {
        /* Unfortunately BPF_ATTACH_TYPE_UNSPEC enumeration doesn't
         * exist so checking for non-zero is the way to go here.
         */
        if (!attr->expected_attach_type) {
            attr->expected_attach_type = BPF_CGROUP_INET_SOCK_CREATE;
        }
    }
}

static int bpf_prog_load_check_attach(enum bpf_prog_type prog_type, enum bpf_attach_type expected_attach_type,
                                      u32 btf_id, u32 prog_fd)
{
    if (btf_id) {
        if (btf_id > BTF_MAX_TYPE) {
            return -EINVAL;
        }

        switch (prog_type) {
            case BPF_PROG_TYPE_TRACING:
            case BPF_PROG_TYPE_LSM:
            case BPF_PROG_TYPE_STRUCT_OPS:
            case BPF_PROG_TYPE_EXT:
                break;
            default:
                return -EINVAL;
        }
    }

    if (prog_fd && prog_type != BPF_PROG_TYPE_TRACING && prog_type != BPF_PROG_TYPE_EXT) {
        return -EINVAL;
    }

    switch (prog_type) {
        case BPF_PROG_TYPE_CGROUP_SOCK:
            switch (expected_attach_type) {
                case BPF_CGROUP_INET_SOCK_CREATE:
                case BPF_CGROUP_INET_SOCK_RELEASE:
                case BPF_CGROUP_INET4_POST_BIND:
                case BPF_CGROUP_INET6_POST_BIND:
                    return 0;
                default:
                    return -EINVAL;
            }
        case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
            switch (expected_attach_type) {
                case BPF_CGROUP_INET4_BIND:
                case BPF_CGROUP_INET6_BIND:
                case BPF_CGROUP_INET4_CONNECT:
                case BPF_CGROUP_INET6_CONNECT:
                case BPF_CGROUP_INET4_GETPEERNAME:
                case BPF_CGROUP_INET6_GETPEERNAME:
                case BPF_CGROUP_INET4_GETSOCKNAME:
                case BPF_CGROUP_INET6_GETSOCKNAME:
                case BPF_CGROUP_UDP4_SENDMSG:
                case BPF_CGROUP_UDP6_SENDMSG:
                case BPF_CGROUP_UDP4_RECVMSG:
                case BPF_CGROUP_UDP6_RECVMSG:
                    return 0;
                default:
                    return -EINVAL;
            }
        case BPF_PROG_TYPE_CGROUP_SKB:
            switch (expected_attach_type) {
                case BPF_CGROUP_INET_INGRESS:
                case BPF_CGROUP_INET_EGRESS:
                    return 0;
                default:
                    return -EINVAL;
            }
        case BPF_PROG_TYPE_CGROUP_SOCKOPT:
            switch (expected_attach_type) {
                case BPF_CGROUP_SETSOCKOPT:
                case BPF_CGROUP_GETSOCKOPT:
                    return 0;
                default:
                    return -EINVAL;
            }
        case BPF_PROG_TYPE_SK_LOOKUP:
            if (expected_attach_type == BPF_SK_LOOKUP) {
                return 0;
            }
            return -EINVAL;
        case BPF_PROG_TYPE_EXT:
            if (expected_attach_type) {
                return -EINVAL;
            }
            fallthrough;
        default:
            return 0;
    }
}

static bool is_net_admin_prog_type(enum bpf_prog_type prog_type)
{
    switch (prog_type) {
        case BPF_PROG_TYPE_SCHED_CLS:
        case BPF_PROG_TYPE_SCHED_ACT:
        case BPF_PROG_TYPE_XDP:
        case BPF_PROG_TYPE_LWT_IN:
        case BPF_PROG_TYPE_LWT_OUT:
        case BPF_PROG_TYPE_LWT_XMIT:
        case BPF_PROG_TYPE_LWT_SEG6LOCAL:
        case BPF_PROG_TYPE_SK_SKB:
        case BPF_PROG_TYPE_SK_MSG:
        case BPF_PROG_TYPE_LIRC_MODE2:
        case BPF_PROG_TYPE_FLOW_DISSECTOR:
        case BPF_PROG_TYPE_CGROUP_DEVICE:
        case BPF_PROG_TYPE_CGROUP_SOCK:
        case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
        case BPF_PROG_TYPE_CGROUP_SOCKOPT:
        case BPF_PROG_TYPE_CGROUP_SYSCTL:
        case BPF_PROG_TYPE_SOCK_OPS:
        case BPF_PROG_TYPE_EXT: /* extends any prog */
            return true;
        case BPF_PROG_TYPE_CGROUP_SKB:
            /* always unpriv */
        case BPF_PROG_TYPE_SK_REUSEPORT:
            /* equivalent to SOCKET_FILTER. need CAP_BPF only */
        default:
            return false;
    }
}

static bool is_perfmon_prog_type(enum bpf_prog_type prog_type)
{
    switch (prog_type) {
        case BPF_PROG_TYPE_KPROBE:
        case BPF_PROG_TYPE_TRACEPOINT:
        case BPF_PROG_TYPE_PERF_EVENT:
        case BPF_PROG_TYPE_RAW_TRACEPOINT:
        case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
        case BPF_PROG_TYPE_TRACING:
        case BPF_PROG_TYPE_LSM:
        case BPF_PROG_TYPE_STRUCT_OPS: /* has access to struct sock */
        case BPF_PROG_TYPE_EXT:        /* extends any prog */
            return true;
        default:
            return false;
    }
}

/* last field in 'union bpf_attr' used by this command */
#define BPF_PROG_LOAD_LAST_FIELD attach_prog_fd

static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
{
    enum bpf_prog_type type = attr->prog_type;
    struct bpf_prog *prog;
    int err;
    char license[128];
    bool is_gpl;

    if (CHECK_ATTR(BPF_PROG_LOAD)) {
        return -EINVAL;
    }

    if (attr->prog_flags & ~(BPF_F_STRICT_ALIGNMENT | BPF_F_ANY_ALIGNMENT | BPF_F_TEST_STATE_FREQ | BPF_F_SLEEPABLE |
                             BPF_F_TEST_RND_HI32)) {
        return -EINVAL;
    }

    if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && (attr->prog_flags & BPF_F_ANY_ALIGNMENT) &&
        !bpf_capable()) {
        return -EPERM;
    }

    /* copy eBPF program license from user space */
    if (strncpy_from_user(license, u64_to_user_ptr(attr->license), sizeof(license) - 1) < 0) {
        return -EFAULT;
    }
    license[sizeof(license) - 1] = 0;

    /* eBPF programs must be GPL compatible to use GPL-ed functions */
    is_gpl = license_is_gpl_compatible(license);

    if (attr->insn_cnt == 0 || attr->insn_cnt > (bpf_capable() ? BPF_COMPLEXITY_LIMIT_INSNS : BPF_MAXINSNS)) {
        return -E2BIG;
    }
    if (type != BPF_PROG_TYPE_SOCKET_FILTER && type != BPF_PROG_TYPE_CGROUP_SKB && !bpf_capable()) {
        return -EPERM;
    }

    if (is_net_admin_prog_type(type) && !capable(CAP_NET_ADMIN) && !capable(CAP_SYS_ADMIN)) {
        return -EPERM;
    }
    if (is_perfmon_prog_type(type) && !perfmon_capable()) {
        return -EPERM;
    }

    bpf_prog_load_fixup_attach_type(attr);
    if (bpf_prog_load_check_attach(type, attr->expected_attach_type, attr->attach_btf_id, attr->attach_prog_fd)) {
        return -EINVAL;
    }

    /* plain bpf_prog allocation */
    prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER);
    if (!prog) {
        return -ENOMEM;
    }

    prog->expected_attach_type = attr->expected_attach_type;
    prog->aux->attach_btf_id = attr->attach_btf_id;
    if (attr->attach_prog_fd) {
        struct bpf_prog *dst_prog;

        dst_prog = bpf_prog_get(attr->attach_prog_fd);
        if (IS_ERR(dst_prog)) {
            err = PTR_ERR(dst_prog);
            goto free_prog_nouncharge;
        }
        prog->aux->dst_prog = dst_prog;
    }

    prog->aux->offload_requested = !!attr->prog_ifindex;
    prog->aux->sleepable = attr->prog_flags & BPF_F_SLEEPABLE;

    err = security_bpf_prog_alloc(prog->aux);
    if (err) {
        goto free_prog_nouncharge;
    }

    err = bpf_prog_charge_memlock(prog);
    if (err) {
        goto free_prog_sec;
    }

    prog->len = attr->insn_cnt;

    err = -EFAULT;
    if (copy_from_user(prog->insns, u64_to_user_ptr(attr->insns), bpf_prog_insn_size(prog)) != 0) {
        goto free_prog;
    }

    prog->orig_prog = NULL;
    prog->jited = 0;

    atomic64_set(&prog->aux->refcnt, 1);
    prog->gpl_compatible = is_gpl ? 1 : 0;

    if (bpf_prog_is_dev_bound(prog->aux)) {
        err = bpf_prog_offload_init(prog, attr);
        if (err) {
            goto free_prog;
        }
    }

    /* find program type: socket_filter vs tracing_filter */
    err = find_prog_type(type, prog);
    if (err < 0) {
        goto free_prog;
    }

    prog->aux->load_time = ktime_get_boottime_ns();
    err = bpf_obj_name_cpy(prog->aux->name, attr->prog_name, sizeof(attr->prog_name));
    if (err < 0) {
        goto free_prog;
    }

    /* run eBPF verifier */
    err = bpf_check(&prog, attr, uattr);
    if (err < 0) {
        goto free_used_maps;
    }

    prog = bpf_prog_select_runtime(prog, &err);
    if (err < 0) {
        goto free_used_maps;
    }

    err = bpf_prog_alloc_id(prog);
    if (err) {
        goto free_used_maps;
    }

    /* Upon success of bpf_prog_alloc_id(), the BPF prog is
     * effectively publicly exposed. However, retrieving via
     * bpf_prog_get_fd_by_id() will take another reference,
     * therefore it cannot be gone underneath us.
     *
     * Only for the time /after/ successful bpf_prog_new_fd()
     * and before returning to userspace, we might just hold
     * one reference and any parallel close on that fd could
     * rip everything out. Hence, below notifications must
     * happen before bpf_prog_new_fd().
     *
     * Also, any failure handling from this point onwards must
     * be using bpf_prog_put() given the program is exposed.
     */
    bpf_prog_kallsyms_add(prog);
    perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_LOAD, 0);
    bpf_audit_prog(prog, BPF_AUDIT_LOAD);

    err = bpf_prog_new_fd(prog);
    if (err < 0) {
        bpf_prog_put(prog);
    }
    return err;

free_used_maps:
    /* In case we have subprogs, we need to wait for a grace
     * period before we can tear down JIT memory since symbols
     * are already exposed under kallsyms.
     */
    _bpf_prog_put_noref(prog, prog->aux->func_cnt);
    return err;
free_prog:
    bpf_prog_uncharge_memlock(prog);
free_prog_sec:
    security_bpf_prog_free(prog->aux);
free_prog_nouncharge:
    bpf_prog_free(prog);
    return err;
}

#define BPF_OBJ_LAST_FIELD file_flags

static int bpf_obj_pin(const union bpf_attr *attr)
{
    if (CHECK_ATTR(BPF_OBJ) || attr->file_flags != 0) {
        return -EINVAL;
    }

    return bpf_obj_pin_user(attr->bpf_fd, u64_to_user_ptr(attr->pathname));
}

static int bpf_obj_get(const union bpf_attr *attr)
{
    if (CHECK_ATTR(BPF_OBJ) || attr->bpf_fd != 0 || attr->file_flags & ~BPF_OBJ_FLAG_MASK) {
        return -EINVAL;
    }

    return bpf_obj_get_user(u64_to_user_ptr(attr->pathname), attr->file_flags);
}

void bpf_link_init(struct bpf_link *link, enum bpf_link_type type, const struct bpf_link_ops *ops,
                   struct bpf_prog *prog)
{
    atomic64_set(&link->refcnt, 1);
    link->type = type;
    link->id = 0;
    link->ops = ops;
    link->prog = prog;
}

static void bpf_link_free_id(int id)
{
    if (!id) {
        return;
    }

    spin_lock_bh(&link_idr_lock);
    idr_remove(&link_idr, id);
    spin_unlock_bh(&link_idr_lock);
}

/* Clean up bpf_link and corresponding anon_inode file and FD. After
 * anon_inode is created, bpf_link can't be just kfree()'d due to deferred
 * anon_inode's release() call. This helper marksbpf_link as
 * defunct, releases anon_inode file and puts reserved FD. bpf_prog's refcnt
 * is not decremented, it's the responsibility of a calling code that failed
 * to complete bpf_link initialization.
 */
void bpf_link_cleanup(struct bpf_link_primer *primer)
{
    primer->link->prog = NULL;
    bpf_link_free_id(primer->id);
    fput(primer->file);
    put_unused_fd(primer->fd);
}

void bpf_link_inc(struct bpf_link *link)
{
    atomic64_inc(&link->refcnt);
}

/* bpf_link_free is guaranteed to be called from process context */
static void bpf_link_free(struct bpf_link *link)
{
    bpf_link_free_id(link->id);
    if (link->prog) {
        /* detach BPF program, clean up used resources */
        link->ops->release(link);
        bpf_prog_put(link->prog);
    }
    /* free bpf_link and its containing memory */
    link->ops->dealloc(link);
}

static void bpf_link_put_deferred(struct work_struct *work)
{
    struct bpf_link *link = container_of(work, struct bpf_link, work);

    bpf_link_free(link);
}

/* bpf_link_put can be called from atomic context, but ensures that resources
 * are freed from process context
 */
void bpf_link_put(struct bpf_link *link)
{
    if (!atomic64_dec_and_test(&link->refcnt)) {
        return;
    }

    if (in_atomic()) {
        INIT_WORK(&link->work, bpf_link_put_deferred);
        schedule_work(&link->work);
    } else {
        bpf_link_free(link);
    }
}

static int bpf_link_release(struct inode *inode, struct file *filp)
{
    struct bpf_link *link = filp->private_data;

    bpf_link_put(link);
    return 0;
}

#ifdef CONFIG_PROC_FS
#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type)
#define BPF_MAP_TYPE(_id, _ops)
#define BPF_LINK_TYPE(_id, _name) [_id] = #_name,
static const char *bpf_link_type_strs[] = {
    [BPF_LINK_TYPE_UNSPEC] = "<invalid>",
#include <linux/bpf_types.h>
};
#undef BPF_PROG_TYPE
#undef BPF_MAP_TYPE
#undef BPF_LINK_TYPE

static void bpf_link_show_fdinfo(struct seq_file *m, struct file *filp)
{
    const struct bpf_link *link = filp->private_data;
    const struct bpf_prog *prog = link->prog;
    char prog_tag[sizeof(prog->tag) * 0x2 + 1] = {};

    bin2hex(prog_tag, prog->tag, sizeof(prog->tag));
    seq_printf(m,
               "link_type:\t%s\n"
               "link_id:\t%u\n"
               "prog_tag:\t%s\n"
               "prog_id:\t%u\n",
               bpf_link_type_strs[link->type], link->id, prog_tag, prog->aux->id);
    if (link->ops->show_fdinfo) {
        link->ops->show_fdinfo(link, m);
    }
}
#endif

static const struct file_operations bpf_link_fops = {
#ifdef CONFIG_PROC_FS
    .show_fdinfo = bpf_link_show_fdinfo,
#endif
    .release = bpf_link_release,
    .read = bpf_dummy_read,
    .write = bpf_dummy_write,
};

static int bpf_link_alloc_id(struct bpf_link *link)
{
    int id;

    idr_preload(GFP_KERNEL);
    spin_lock_bh(&link_idr_lock);
    id = idr_alloc_cyclic(&link_idr, link, 1, INT_MAX, GFP_ATOMIC);
    spin_unlock_bh(&link_idr_lock);
    idr_preload_end();

    return id;
}

/* Prepare bpf_link to be exposed to user-space by allocating anon_inode file,
 * reserving unused FD and allocating ID from link_idr. This is to be paired
 * with bpf_link_settle() to install FD and ID and expose bpf_link to
 * user-space, if bpf_link is successfully attached. If not, bpf_link and
 * pre-allocated resources are to be freed with bpf_cleanup() call. All the
 * transient state is passed around in struct bpf_link_primer.
 * This is preferred way to create and initialize bpf_link, especially when
 * there are complicated and expensive operations inbetween creating bpf_link
 * itself and attaching it to BPF hook. By using bpf_link_prime() and
 * bpf_link_settle() kernel code using bpf_link doesn't have to perform
 * expensive (and potentially failing) roll back operations in a rare case
 * that file, FD, or ID can't be allocated.
 */
int bpf_link_prime(struct bpf_link *link, struct bpf_link_primer *primer)
{
    struct file *file;
    int fd, id;

    fd = get_unused_fd_flags(O_CLOEXEC);
    if (fd < 0) {
        return fd;
    }

    id = bpf_link_alloc_id(link);
    if (id < 0) {
        put_unused_fd(fd);
        return id;
    }

    file = anon_inode_getfile("bpf_link", &bpf_link_fops, link, O_CLOEXEC);
    if (IS_ERR(file)) {
        bpf_link_free_id(id);
        put_unused_fd(fd);
        return PTR_ERR(file);
    }

    primer->link = link;
    primer->file = file;
    primer->fd = fd;
    primer->id = id;
    return 0;
}

int bpf_link_settle(struct bpf_link_primer *primer)
{
    /* make bpf_link fetchable by ID */
    spin_lock_bh(&link_idr_lock);
    primer->link->id = primer->id;
    spin_unlock_bh(&link_idr_lock);
    /* make bpf_link fetchable by FD */
    fd_install(primer->fd, primer->file);
    /* pass through installed FD */
    return primer->fd;
}

int bpf_link_new_fd(struct bpf_link *link)
{
    return anon_inode_getfd("bpf-link", &bpf_link_fops, link, O_CLOEXEC);
}

struct bpf_link *bpf_link_get_from_fd(u32 ufd)
{
    struct fd f = fdget(ufd);
    struct bpf_link *link;

    if (!f.file) {
        return ERR_PTR(-EBADF);
    }
    if (f.file->f_op != &bpf_link_fops) {
        fdput(f);
        return ERR_PTR(-EINVAL);
    }

    link = f.file->private_data;
    bpf_link_inc(link);
    fdput(f);

    return link;
}

struct bpf_tracing_link {
    struct bpf_link link;
    enum bpf_attach_type attach_type;
    struct bpf_trampoline *trampoline;
    struct bpf_prog *tgt_prog;
};

static void bpf_tracing_link_release(struct bpf_link *link)
{
    struct bpf_tracing_link *tr_link = container_of(link, struct bpf_tracing_link, link);

    WARN_ON_ONCE(bpf_trampoline_unlink_prog(link->prog, tr_link->trampoline));

    bpf_trampoline_put(tr_link->trampoline);

    /* tgt_prog is NULL if target is a kernel function */
    if (tr_link->tgt_prog) {
        bpf_prog_put(tr_link->tgt_prog);
    }
}

static void bpf_tracing_link_dealloc(struct bpf_link *link)
{
    struct bpf_tracing_link *tr_link = container_of(link, struct bpf_tracing_link, link);

    kfree(tr_link);
}

static void bpf_tracing_link_show_fdinfo(const struct bpf_link *link, struct seq_file *seq)
{
    struct bpf_tracing_link *tr_link = container_of(link, struct bpf_tracing_link, link);

    seq_printf(seq, "attach_type:\t%d\n", tr_link->attach_type);
}

static int bpf_tracing_link_fill_link_info(const struct bpf_link *link, struct bpf_link_info *info)
{
    struct bpf_tracing_link *tr_link = container_of(link, struct bpf_tracing_link, link);

    info->tracing.attach_type = tr_link->attach_type;

    return 0;
}

static const struct bpf_link_ops bpf_tracing_link_lops = {
    .release = bpf_tracing_link_release,
    .dealloc = bpf_tracing_link_dealloc,
    .show_fdinfo = bpf_tracing_link_show_fdinfo,
    .fill_link_info = bpf_tracing_link_fill_link_info,
};

static int bpf_tracing_prog_attach(struct bpf_prog *prog, int tgt_prog_fd, u32 btf_id)
{
    struct bpf_link_primer link_primer;
    struct bpf_prog *tgt_prog = NULL;
    struct bpf_trampoline *tr = NULL;
    struct bpf_tracing_link *link;
    u64 key = 0;
    int err;

    switch (prog->type) {
        case BPF_PROG_TYPE_TRACING:
            if (prog->expected_attach_type != BPF_TRACE_FENTRY && prog->expected_attach_type != BPF_TRACE_FEXIT &&
                prog->expected_attach_type != BPF_MODIFY_RETURN) {
                err = -EINVAL;
                goto out_put_prog;
            }
            break;
        case BPF_PROG_TYPE_EXT:
            if (prog->expected_attach_type != 0) {
                err = -EINVAL;
                goto out_put_prog;
            }
            break;
        case BPF_PROG_TYPE_LSM:
            if (prog->expected_attach_type != BPF_LSM_MAC) {
                err = -EINVAL;
                goto out_put_prog;
            }
            break;
        default:
            err = -EINVAL;
            goto out_put_prog;
    }

    if (!!tgt_prog_fd != !!btf_id) {
        err = -EINVAL;
        goto out_put_prog;
    }

    if (tgt_prog_fd) {
        /* For now we only allow new targets for BPF_PROG_TYPE_EXT */
        if (prog->type != BPF_PROG_TYPE_EXT) {
            err = -EINVAL;
            goto out_put_prog;
        }

        tgt_prog = bpf_prog_get(tgt_prog_fd);
        if (IS_ERR(tgt_prog)) {
            err = PTR_ERR(tgt_prog);
            tgt_prog = NULL;
            goto out_put_prog;
        }

        key = bpf_trampoline_compute_key(tgt_prog, btf_id);
    }

    link = kzalloc(sizeof(*link), GFP_USER);
    if (!link) {
        err = -ENOMEM;
        goto out_put_prog;
    }
    bpf_link_init(&link->link, BPF_LINK_TYPE_TRACING, &bpf_tracing_link_lops, prog);
    link->attach_type = prog->expected_attach_type;

    mutex_lock(&prog->aux->dst_mutex);

    /* There are a few possible cases here:
     *
     * - if prog->aux->dst_trampoline is set, the program was just loaded
     *   and not yet attached to anything, so we can use the values stored
     *   in prog->aux
     *
     * - if prog->aux->dst_trampoline is NULL, the program has already been
     *   attached to a target and its initial target was cleared (below)
     *
     * - if tgt_prog != NULL, the caller specified tgt_prog_fd +
     *   target_btf_id using the link_create API.
     *
     * - if tgt_prog == NULL when this function was called using the old
     *   raw_tracepoint_open API, and we need a target from prog->aux
     *
     * The combination of no saved target in prog->aux, and no target
     * specified on load is illegal, and we reject that here.
     */
    if (!prog->aux->dst_trampoline && !tgt_prog) {
        err = -ENOENT;
        goto out_unlock;
    }

    if (!prog->aux->dst_trampoline || (key && key != prog->aux->dst_trampoline->key)) {
        /* If there is no saved target, or the specified target is
         * different from the destination specified at load time, we
         * need a new trampoline and a check for compatibility
         */
        struct bpf_attach_target_info tgt_info = {};

        err = bpf_check_attach_target(NULL, prog, tgt_prog, btf_id, &tgt_info);
        if (err) {
            goto out_unlock;
        }

        tr = bpf_trampoline_get(key, &tgt_info);
        if (!tr) {
            err = -ENOMEM;
            goto out_unlock;
        }
    } else {
        /* The caller didn't specify a target, or the target was the
         * same as the destination supplied during program load. This
         * means we can reuse the trampoline and reference from program
         * load time, and there is no need to allocate a new one. This
         * can only happen once for any program, as the saved values in
         * prog->aux are cleared below.
         */
        tr = prog->aux->dst_trampoline;
        tgt_prog = prog->aux->dst_prog;
    }

    err = bpf_link_prime(&link->link, &link_primer);
    if (err) {
        goto out_unlock;
    }

    err = bpf_trampoline_link_prog(prog, tr);
    if (err) {
        bpf_link_cleanup(&link_primer);
        link = NULL;
        goto out_unlock;
    }

    link->tgt_prog = tgt_prog;
    link->trampoline = tr;

    /* Always clear the trampoline and target prog from prog->aux to make
     * sure the original attach destination is not kept alive after a
     * program is (re-)attached to another target.
     */
    if (prog->aux->dst_prog && (tgt_prog_fd || tr != prog->aux->dst_trampoline)) {
        /* got extra prog ref from syscall, or attaching to different prog */
        bpf_prog_put(prog->aux->dst_prog);
    }
    if (prog->aux->dst_trampoline && tr != prog->aux->dst_trampoline) {
        /* we allocated a new trampoline, so free the old one */
        bpf_trampoline_put(prog->aux->dst_trampoline);
    }

    prog->aux->dst_prog = NULL;
    prog->aux->dst_trampoline = NULL;
    mutex_unlock(&prog->aux->dst_mutex);

    return bpf_link_settle(&link_primer);
out_unlock:
    if (tr && tr != prog->aux->dst_trampoline) {
        bpf_trampoline_put(tr);
    }
    mutex_unlock(&prog->aux->dst_mutex);
    kfree(link);
out_put_prog:
    if (tgt_prog_fd && tgt_prog) {
        bpf_prog_put(tgt_prog);
    }
    return err;
}

struct bpf_raw_tp_link {
    struct bpf_link link;
    struct bpf_raw_event_map *btp;
};

static void bpf_raw_tp_link_release(struct bpf_link *link)
{
    struct bpf_raw_tp_link *raw_tp = container_of(link, struct bpf_raw_tp_link, link);

    bpf_probe_unregister(raw_tp->btp, raw_tp->link.prog);
    bpf_put_raw_tracepoint(raw_tp->btp);
}

static void bpf_raw_tp_link_dealloc(struct bpf_link *link)
{
    struct bpf_raw_tp_link *raw_tp = container_of(link, struct bpf_raw_tp_link, link);

    kfree(raw_tp);
}

static void bpf_raw_tp_link_show_fdinfo(const struct bpf_link *link, struct seq_file *seq)
{
    struct bpf_raw_tp_link *raw_tp_link = container_of(link, struct bpf_raw_tp_link, link);

    seq_printf(seq, "tp_name:\t%s\n", raw_tp_link->btp->tp->name);
}

static int bpf_raw_tp_link_fill_link_info(const struct bpf_link *link, struct bpf_link_info *info)
{
    struct bpf_raw_tp_link *raw_tp_link = container_of(link, struct bpf_raw_tp_link, link);
    char __user *ubuf = u64_to_user_ptr(info->raw_tracepoint.tp_name);
    const char *tp_name = raw_tp_link->btp->tp->name;
    u32 ulen = info->raw_tracepoint.tp_name_len;
    size_t tp_len = strlen(tp_name);

    if (!ulen ^ !ubuf) {
        return -EINVAL;
    }

    info->raw_tracepoint.tp_name_len = tp_len + 1;

    if (!ubuf) {
        return 0;
    }

    if (ulen >= tp_len + 1) {
        if (copy_to_user(ubuf, tp_name, tp_len + 1)) {
            return -EFAULT;
        }
    } else {
        char zero = '\0';

        if (copy_to_user(ubuf, tp_name, ulen - 1)) {
            return -EFAULT;
        }
        if (put_user(zero, ubuf + ulen - 1)) {
            return -EFAULT;
        }
        return -ENOSPC;
    }

    return 0;
}

static const struct bpf_link_ops bpf_raw_tp_link_lops = {
    .release = bpf_raw_tp_link_release,
    .dealloc = bpf_raw_tp_link_dealloc,
    .show_fdinfo = bpf_raw_tp_link_show_fdinfo,
    .fill_link_info = bpf_raw_tp_link_fill_link_info,
};

#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd

static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
{
    struct bpf_link_primer link_primer;
    struct bpf_raw_tp_link *link;
    struct bpf_raw_event_map *btp;
    struct bpf_prog *prog;
    const char *tp_name;
    char buf[128];
    int err;

    if (CHECK_ATTR(BPF_RAW_TRACEPOINT_OPEN)) {
        return -EINVAL;
    }

    prog = bpf_prog_get(attr->raw_tracepoint.prog_fd);
    if (IS_ERR(prog)) {
        return PTR_ERR(prog);
    }

    switch (prog->type) {
        case BPF_PROG_TYPE_TRACING:
        case BPF_PROG_TYPE_EXT:
        case BPF_PROG_TYPE_LSM:
            if (attr->raw_tracepoint.name) {
                /* The attach point for this category of programs
                 * should be specified via btf_id during program load.
                 */
                err = -EINVAL;
                goto out_put_prog;
            }
            if (prog->type == BPF_PROG_TYPE_TRACING && prog->expected_attach_type == BPF_TRACE_RAW_TP) {
                tp_name = prog->aux->attach_func_name;
                break;
            }
            err = bpf_tracing_prog_attach(prog, 0, 0);
            if (err >= 0) {
                return err;
            }
            goto out_put_prog;
        case BPF_PROG_TYPE_RAW_TRACEPOINT:
        case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
            if (strncpy_from_user(buf, u64_to_user_ptr(attr->raw_tracepoint.name), sizeof(buf) - 1) < 0) {
                err = -EFAULT;
                goto out_put_prog;
            }
            buf[sizeof(buf) - 1] = 0;
            tp_name = buf;
            break;
        default:
            err = -EINVAL;
            goto out_put_prog;
    }

    btp = bpf_get_raw_tracepoint(tp_name);
    if (!btp) {
        err = -ENOENT;
        goto out_put_prog;
    }

    link = kzalloc(sizeof(*link), GFP_USER);
    if (!link) {
        err = -ENOMEM;
        goto out_put_btp;
    }
    bpf_link_init(&link->link, BPF_LINK_TYPE_RAW_TRACEPOINT, &bpf_raw_tp_link_lops, prog);
    link->btp = btp;

    err = bpf_link_prime(&link->link, &link_primer);
    if (err) {
        kfree(link);
        goto out_put_btp;
    }

    err = bpf_probe_register(link->btp, prog);
    if (err) {
        bpf_link_cleanup(&link_primer);
        goto out_put_btp;
    }

    return bpf_link_settle(&link_primer);

out_put_btp:
    bpf_put_raw_tracepoint(btp);
out_put_prog:
    bpf_prog_put(prog);
    return err;
}

static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog, enum bpf_attach_type attach_type)
{
    switch (prog->type) {
        case BPF_PROG_TYPE_CGROUP_SOCK:
        case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
        case BPF_PROG_TYPE_CGROUP_SOCKOPT:
        case BPF_PROG_TYPE_SK_LOOKUP:
            return attach_type == prog->expected_attach_type ? 0 : -EINVAL;
        case BPF_PROG_TYPE_CGROUP_SKB:
            if (!capable(CAP_NET_ADMIN)) {
                /* cg-skb progs can be loaded by unpriv user.
                 * check permissions at attach time.
                 */
                return -EPERM;
            }
            return prog->enforce_expected_attach_type && prog->expected_attach_type != attach_type ? -EINVAL : 0;
        default:
            return 0;
    }
}

static enum bpf_prog_type attach_type_to_prog_type(enum bpf_attach_type attach_type)
{
    switch (attach_type) {
        case BPF_CGROUP_INET_INGRESS:
        case BPF_CGROUP_INET_EGRESS:
            return BPF_PROG_TYPE_CGROUP_SKB;
        case BPF_CGROUP_INET_SOCK_CREATE:
        case BPF_CGROUP_INET_SOCK_RELEASE:
        case BPF_CGROUP_INET4_POST_BIND:
        case BPF_CGROUP_INET6_POST_BIND:
            return BPF_PROG_TYPE_CGROUP_SOCK;
        case BPF_CGROUP_INET4_BIND:
        case BPF_CGROUP_INET6_BIND:
        case BPF_CGROUP_INET4_CONNECT:
        case BPF_CGROUP_INET6_CONNECT:
        case BPF_CGROUP_INET4_GETPEERNAME:
        case BPF_CGROUP_INET6_GETPEERNAME:
        case BPF_CGROUP_INET4_GETSOCKNAME:
        case BPF_CGROUP_INET6_GETSOCKNAME:
        case BPF_CGROUP_UDP4_SENDMSG:
        case BPF_CGROUP_UDP6_SENDMSG:
        case BPF_CGROUP_UDP4_RECVMSG:
        case BPF_CGROUP_UDP6_RECVMSG:
            return BPF_PROG_TYPE_CGROUP_SOCK_ADDR;
        case BPF_CGROUP_SOCK_OPS:
            return BPF_PROG_TYPE_SOCK_OPS;
        case BPF_CGROUP_DEVICE:
            return BPF_PROG_TYPE_CGROUP_DEVICE;
        case BPF_SK_MSG_VERDICT:
            return BPF_PROG_TYPE_SK_MSG;
        case BPF_SK_SKB_STREAM_PARSER:
        case BPF_SK_SKB_STREAM_VERDICT:
            return BPF_PROG_TYPE_SK_SKB;
        case BPF_LIRC_MODE2:
            return BPF_PROG_TYPE_LIRC_MODE2;
        case BPF_FLOW_DISSECTOR:
            return BPF_PROG_TYPE_FLOW_DISSECTOR;
        case BPF_CGROUP_SYSCTL:
            return BPF_PROG_TYPE_CGROUP_SYSCTL;
        case BPF_CGROUP_GETSOCKOPT:
        case BPF_CGROUP_SETSOCKOPT:
            return BPF_PROG_TYPE_CGROUP_SOCKOPT;
        case BPF_TRACE_ITER:
            return BPF_PROG_TYPE_TRACING;
        case BPF_SK_LOOKUP:
            return BPF_PROG_TYPE_SK_LOOKUP;
        case BPF_XDP:
            return BPF_PROG_TYPE_XDP;
        default:
            return BPF_PROG_TYPE_UNSPEC;
    }
}

#define BPF_PROG_ATTACH_LAST_FIELD replace_bpf_fd

#define BPF_F_ATTACH_MASK (BPF_F_ALLOW_OVERRIDE | BPF_F_ALLOW_MULTI | BPF_F_REPLACE)

static int bpf_prog_attach(const union bpf_attr *attr)
{
    enum bpf_prog_type ptype;
    struct bpf_prog *prog;
    int ret;

    if (CHECK_ATTR(BPF_PROG_ATTACH)) {
        return -EINVAL;
    }

    if (attr->attach_flags & ~BPF_F_ATTACH_MASK) {
        return -EINVAL;
    }

    ptype = attach_type_to_prog_type(attr->attach_type);
    if (ptype == BPF_PROG_TYPE_UNSPEC) {
        return -EINVAL;
    }

    prog = bpf_prog_get_type(attr->attach_bpf_fd, ptype);
    if (IS_ERR(prog)) {
        return PTR_ERR(prog);
    }

    if (bpf_prog_attach_check_attach_type(prog, attr->attach_type)) {
        bpf_prog_put(prog);
        return -EINVAL;
    }

    switch (ptype) {
        case BPF_PROG_TYPE_SK_SKB:
        case BPF_PROG_TYPE_SK_MSG:
            ret = sock_map_get_from_fd(attr, prog);
            break;
        case BPF_PROG_TYPE_LIRC_MODE2:
            ret = lirc_prog_attach(attr, prog);
            break;
        case BPF_PROG_TYPE_FLOW_DISSECTOR:
            ret = netns_bpf_prog_attach(attr, prog);
            break;
        case BPF_PROG_TYPE_CGROUP_DEVICE:
        case BPF_PROG_TYPE_CGROUP_SKB:
        case BPF_PROG_TYPE_CGROUP_SOCK:
        case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
        case BPF_PROG_TYPE_CGROUP_SOCKOPT:
        case BPF_PROG_TYPE_CGROUP_SYSCTL:
        case BPF_PROG_TYPE_SOCK_OPS:
            ret = cgroup_bpf_prog_attach(attr, ptype, prog);
            break;
        default:
            ret = -EINVAL;
    }

    if (ret) {
        bpf_prog_put(prog);
    }
    return ret;
}

#define BPF_PROG_DETACH_LAST_FIELD attach_type

static int bpf_prog_detach(const union bpf_attr *attr)
{
    enum bpf_prog_type ptype;

    if (CHECK_ATTR(BPF_PROG_DETACH)) {
        return -EINVAL;
    }

    ptype = attach_type_to_prog_type(attr->attach_type);

    switch (ptype) {
        case BPF_PROG_TYPE_SK_MSG:
        case BPF_PROG_TYPE_SK_SKB:
            return sock_map_prog_detach(attr, ptype);
        case BPF_PROG_TYPE_LIRC_MODE2:
            return lirc_prog_detach(attr);
        case BPF_PROG_TYPE_FLOW_DISSECTOR:
            return netns_bpf_prog_detach(attr, ptype);
        case BPF_PROG_TYPE_CGROUP_DEVICE:
        case BPF_PROG_TYPE_CGROUP_SKB:
        case BPF_PROG_TYPE_CGROUP_SOCK:
        case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
        case BPF_PROG_TYPE_CGROUP_SOCKOPT:
        case BPF_PROG_TYPE_CGROUP_SYSCTL:
        case BPF_PROG_TYPE_SOCK_OPS:
            return cgroup_bpf_prog_detach(attr, ptype);
        default:
            return -EINVAL;
    }
}

#define BPF_PROG_QUERY_LAST_FIELD query.prog_cnt

static int bpf_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr)
{
    if (!capable(CAP_NET_ADMIN)) {
        return -EPERM;
    }
    if (CHECK_ATTR(BPF_PROG_QUERY)) {
        return -EINVAL;
    }
    if (attr->query.query_flags & ~BPF_F_QUERY_EFFECTIVE) {
        return -EINVAL;
    }

    switch (attr->query.attach_type) {
        case BPF_CGROUP_INET_INGRESS:
        case BPF_CGROUP_INET_EGRESS:
        case BPF_CGROUP_INET_SOCK_CREATE:
        case BPF_CGROUP_INET_SOCK_RELEASE:
        case BPF_CGROUP_INET4_BIND:
        case BPF_CGROUP_INET6_BIND:
        case BPF_CGROUP_INET4_POST_BIND:
        case BPF_CGROUP_INET6_POST_BIND:
        case BPF_CGROUP_INET4_CONNECT:
        case BPF_CGROUP_INET6_CONNECT:
        case BPF_CGROUP_INET4_GETPEERNAME:
        case BPF_CGROUP_INET6_GETPEERNAME:
        case BPF_CGROUP_INET4_GETSOCKNAME:
        case BPF_CGROUP_INET6_GETSOCKNAME:
        case BPF_CGROUP_UDP4_SENDMSG:
        case BPF_CGROUP_UDP6_SENDMSG:
        case BPF_CGROUP_UDP4_RECVMSG:
        case BPF_CGROUP_UDP6_RECVMSG:
        case BPF_CGROUP_SOCK_OPS:
        case BPF_CGROUP_DEVICE:
        case BPF_CGROUP_SYSCTL:
        case BPF_CGROUP_GETSOCKOPT:
        case BPF_CGROUP_SETSOCKOPT:
            return cgroup_bpf_prog_query(attr, uattr);
        case BPF_LIRC_MODE2:
            return lirc_prog_query(attr, uattr);
        case BPF_FLOW_DISSECTOR:
        case BPF_SK_LOOKUP:
            return netns_bpf_prog_query(attr, uattr);
        default:
            return -EINVAL;
    }
}

#define BPF_PROG_TEST_RUN_LAST_FIELD test.cpu

static int bpf_prog_test_run(const union bpf_attr *attr, union bpf_attr __user *uattr)
{
    struct bpf_prog *prog;
    int ret = -ENOTSUPP;

    if (CHECK_ATTR(BPF_PROG_TEST_RUN)) {
        return -EINVAL;
    }

    if ((attr->test.ctx_size_in && !attr->test.ctx_in) || (!attr->test.ctx_size_in && attr->test.ctx_in)) {
        return -EINVAL;
    }

    if ((attr->test.ctx_size_out && !attr->test.ctx_out) || (!attr->test.ctx_size_out && attr->test.ctx_out)) {
        return -EINVAL;
    }

    prog = bpf_prog_get(attr->test.prog_fd);
    if (IS_ERR(prog)) {
        return PTR_ERR(prog);
    }

    if (prog->aux->ops->test_run) {
        ret = prog->aux->ops->test_run(prog, attr, uattr);
    }

    bpf_prog_put(prog);
    return ret;
}

#define BPF_OBJ_GET_NEXT_ID_LAST_FIELD next_id

static int bpf_obj_get_next_id(const union bpf_attr *attr, union bpf_attr __user *uattr, struct idr *idr,
                               spinlock_t *lock)
{
    u32 next_id = attr->start_id;
    int err = 0;

    if (CHECK_ATTR(BPF_OBJ_GET_NEXT_ID) || next_id >= INT_MAX) {
        return -EINVAL;
    }

    if (!capable(CAP_SYS_ADMIN)) {
        return -EPERM;
    }

    next_id++;
    spin_lock_bh(lock);
    if (!idr_get_next(idr, &next_id)) {
        err = -ENOENT;
    }
    spin_unlock_bh(lock);

    if (!err) {
        err = put_user(next_id, &uattr->next_id);
    }

    return err;
}

struct bpf_map *bpf_map_get_curr_or_next(u32 *id)
{
    struct bpf_map *map;

    spin_lock_bh(&map_idr_lock);

    while (1) {
        map = idr_get_next(&map_idr, id);
        if (map) {
            map = _bpf_map_inc_not_zero(map, false);
            if (IS_ERR(map)) {
                (*id)++;
                continue;
            }
        }
        break;
    }
    spin_unlock_bh(&map_idr_lock);

    return map;
}

struct bpf_prog *bpf_prog_get_curr_or_next(u32 *id)
{
    struct bpf_prog *prog;

    spin_lock_bh(&prog_idr_lock);
    while (1) {
        prog = idr_get_next(&prog_idr, id);
        if (prog) {
            prog = bpf_prog_inc_not_zero(prog);
            if (IS_ERR(prog)) {
                (*id)++;
                continue;
            }
        }
        break;
    }
    spin_unlock_bh(&prog_idr_lock);

    return prog;
}

#define BPF_PROG_GET_FD_BY_ID_LAST_FIELD prog_id

struct bpf_prog *bpf_prog_by_id(u32 id)
{
    struct bpf_prog *prog;

    if (!id) {
        return ERR_PTR(-ENOENT);
    }

    spin_lock_bh(&prog_idr_lock);
    prog = idr_find(&prog_idr, id);
    if (prog) {
        prog = bpf_prog_inc_not_zero(prog);
    } else {
        prog = ERR_PTR(-ENOENT);
    }
    spin_unlock_bh(&prog_idr_lock);
    return prog;
}

static int bpf_prog_get_fd_by_id(const union bpf_attr *attr)
{
    struct bpf_prog *prog;
    u32 id = attr->prog_id;
    int fd;

    if (CHECK_ATTR(BPF_PROG_GET_FD_BY_ID)) {
        return -EINVAL;
    }

    if (!capable(CAP_SYS_ADMIN)) {
        return -EPERM;
    }

    prog = bpf_prog_by_id(id);
    if (IS_ERR(prog)) {
        return PTR_ERR(prog);
    }

    fd = bpf_prog_new_fd(prog);
    if (fd < 0) {
        bpf_prog_put(prog);
    }

    return fd;
}

#define BPF_MAP_GET_FD_BY_ID_LAST_FIELD open_flags

static int bpf_map_get_fd_by_id(const union bpf_attr *attr)
{
    struct bpf_map *map;
    u32 id = attr->map_id;
    int f_flags;
    int fd;

    if (CHECK_ATTR(BPF_MAP_GET_FD_BY_ID) || attr->open_flags & ~BPF_OBJ_FLAG_MASK) {
        return -EINVAL;
    }

    if (!capable(CAP_SYS_ADMIN)) {
        return -EPERM;
    }

    f_flags = bpf_get_file_flag(attr->open_flags);
    if (f_flags < 0) {
        return f_flags;
    }

    spin_lock_bh(&map_idr_lock);
    map = idr_find(&map_idr, id);
    if (map) {
        map = _bpf_map_inc_not_zero(map, true);
    } else {
        map = ERR_PTR(-ENOENT);
    }
    spin_unlock_bh(&map_idr_lock);

    if (IS_ERR(map)) {
        return PTR_ERR(map);
    }

    fd = bpf_map_new_fd(map, f_flags);
    if (fd < 0) {
        bpf_map_put_with_uref(map);
    }

    return fd;
}

static const struct bpf_map *bpf_map_from_imm(const struct bpf_prog *prog, unsigned long addr, u32 *off, u32 *type)
{
    const struct bpf_map *map;
    int i;

    mutex_lock(&prog->aux->used_maps_mutex);
    for (i = 0, *off = 0; i < prog->aux->used_map_cnt; i++) {
        map = prog->aux->used_maps[i];
        if (map == (void *)addr) {
            *type = BPF_PSEUDO_MAP_FD;
            goto out;
        }
        if (!map->ops->map_direct_value_meta) {
            continue;
        }
        if (!map->ops->map_direct_value_meta(map, addr, off)) {
            *type = BPF_PSEUDO_MAP_VALUE;
            goto out;
        }
    }
    map = NULL;

out:
    mutex_unlock(&prog->aux->used_maps_mutex);
    return map;
}

static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog, const struct cred *f_cred)
{
    const struct bpf_map *map;
    struct bpf_insn *insns;
    u32 off, type;
    u64 imm;
    u8 code;
    int i;

    insns = kmemdup(prog->insnsi, bpf_prog_insn_size(prog), GFP_USER);
    if (!insns) {
        return insns;
    }

    for (i = 0; i < prog->len; i++) {
        code = insns[i].code;

        if (code == (BPF_JMP | BPF_TAIL_CALL)) {
            insns[i].code = BPF_JMP | BPF_CALL;
            insns[i].imm = BPF_FUNC_tail_call;
            /* fall-through */
        }
        if (code == (BPF_JMP | BPF_CALL) || code == (BPF_JMP | BPF_CALL_ARGS)) {
            if (code == (BPF_JMP | BPF_CALL_ARGS)) {
                insns[i].code = BPF_JMP | BPF_CALL;
            }
            if (!bpf_dump_raw_ok(f_cred)) {
                insns[i].imm = 0;
            }
            continue;
        }
        if (BPF_CLASS(code) == BPF_LDX && BPF_MODE(code) == BPF_PROBE_MEM) {
            insns[i].code = BPF_LDX | BPF_SIZE(code) | BPF_MEM;
            continue;
        }

        if (code != (BPF_LD | BPF_IMM | BPF_DW)) {
            continue;
        }

        imm = ((u64)insns[i + 1].imm << 32) | (u32)insns[i].imm;
        map = bpf_map_from_imm(prog, imm, &off, &type);
        if (map) {
            insns[i].src_reg = type;
            insns[i].imm = map->id;
            insns[i + 1].imm = off;
            continue;
        }
    }

    return insns;
}

static int set_info_rec_size(struct bpf_prog_info *info)
{
    /*
     * Ensure info.*_rec_size is the same as kernel expected size
     *
     * or
     *
     * Only allow zero *_rec_size if both _rec_size and _cnt are
     * zero.  In this case, the kernel will set the expected
     * _rec_size back to the info.
     */

    if ((info->nr_func_info || info->func_info_rec_size) && info->func_info_rec_size != sizeof(struct bpf_func_info)) {
        return -EINVAL;
    }

    if ((info->nr_line_info || info->line_info_rec_size) && info->line_info_rec_size != sizeof(struct bpf_line_info)) {
        return -EINVAL;
    }

    if ((info->nr_jited_line_info || info->jited_line_info_rec_size) &&
        info->jited_line_info_rec_size != sizeof(__u64)) {
        return -EINVAL;
    }

    info->func_info_rec_size = sizeof(struct bpf_func_info);
    info->line_info_rec_size = sizeof(struct bpf_line_info);
    info->jited_line_info_rec_size = sizeof(__u64);

    return 0;
}

static int bpf_prog_get_info_by_fd(struct file *file, struct bpf_prog *prog, const union bpf_attr *attr,
                                   union bpf_attr __user *uattr)
{
    struct bpf_prog_info __user *uinfo = u64_to_user_ptr(attr->info.info);
    struct bpf_prog_info info;
    u32 info_len = attr->info.info_len;
    struct bpf_prog_stats stats;
    char __user *uinsns;
    u32 ulen;
    int err;

    err = bpf_check_uarg_tail_zero(uinfo, sizeof(info), info_len);
    if (err) {
        return err;
    }
    info_len = min_t(u32, sizeof(info), info_len);

    memset(&info, 0, sizeof(info));
    if (copy_from_user(&info, uinfo, info_len)) {
        return -EFAULT;
    }

    info.type = prog->type;
    info.id = prog->aux->id;
    info.load_time = prog->aux->load_time;
    info.created_by_uid = from_kuid_munged(current_user_ns(), prog->aux->user->uid);
    info.gpl_compatible = prog->gpl_compatible;

    memcpy(info.tag, prog->tag, sizeof(prog->tag));
    memcpy(info.name, prog->aux->name, sizeof(prog->aux->name));

    mutex_lock(&prog->aux->used_maps_mutex);
    ulen = info.nr_map_ids;
    info.nr_map_ids = prog->aux->used_map_cnt;
    ulen = min_t(u32, info.nr_map_ids, ulen);
    if (ulen) {
        u32 __user *user_map_ids = u64_to_user_ptr(info.map_ids);
        u32 i;

        for (i = 0; i < ulen; i++) {
            if (put_user(prog->aux->used_maps[i]->id, &user_map_ids[i])) {
                mutex_unlock(&prog->aux->used_maps_mutex);
                return -EFAULT;
            }
        }
    }
    mutex_unlock(&prog->aux->used_maps_mutex);

    err = set_info_rec_size(&info);
    if (err) {
        return err;
    }

    bpf_prog_get_stats(prog, &stats);
    info.run_time_ns = stats.nsecs;
    info.run_cnt = stats.cnt;

    if (!bpf_capable()) {
        info.jited_prog_len = 0;
        info.xlated_prog_len = 0;
        info.nr_jited_ksyms = 0;
        info.nr_jited_func_lens = 0;
        info.nr_func_info = 0;
        info.nr_line_info = 0;
        info.nr_jited_line_info = 0;
        goto done;
    }

    ulen = info.xlated_prog_len;
    info.xlated_prog_len = bpf_prog_insn_size(prog);
    if (info.xlated_prog_len && ulen) {
        struct bpf_insn *insns_sanitized;
        bool fault;

        if (prog->blinded && !bpf_dump_raw_ok(file->f_cred)) {
            info.xlated_prog_insns = 0;
            goto done;
        }
        insns_sanitized = bpf_insn_prepare_dump(prog, file->f_cred);
        if (!insns_sanitized) {
            return -ENOMEM;
        }
        uinsns = u64_to_user_ptr(info.xlated_prog_insns);
        ulen = min_t(u32, info.xlated_prog_len, ulen);
        fault = copy_to_user(uinsns, insns_sanitized, ulen);
        kfree(insns_sanitized);
        if (fault) {
            return -EFAULT;
        }
    }

    if (bpf_prog_is_dev_bound(prog->aux)) {
        err = bpf_prog_offload_info_fill(&info, prog);
        if (err) {
            return err;
        }
        goto done;
    }

    /* NOTE: the following code is supposed to be skipped for offload.
     * bpf_prog_offload_info_fill() is the place to fill similar fields
     * for offload.
     */
    ulen = info.jited_prog_len;
    if (prog->aux->func_cnt) {
        u32 i;

        info.jited_prog_len = 0;
        for (i = 0; i < prog->aux->func_cnt; i++) {
            info.jited_prog_len += prog->aux->func[i]->jited_len;
        }
    } else {
        info.jited_prog_len = prog->jited_len;
    }

    if (info.jited_prog_len && ulen) {
        if (bpf_dump_raw_ok(file->f_cred)) {
            uinsns = u64_to_user_ptr(info.jited_prog_insns);
            ulen = min_t(u32, info.jited_prog_len, ulen);

            /* for multi-function programs, copy the JITed
             * instructions for all the functions
             */
            if (prog->aux->func_cnt) {
                u32 len, free, i;
                u8 *img;

                free = ulen;
                for (i = 0; i < prog->aux->func_cnt; i++) {
                    len = prog->aux->func[i]->jited_len;
                    len = min_t(u32, len, free);
                    img = (u8 *)prog->aux->func[i]->bpf_func;
                    if (copy_to_user(uinsns, img, len)) {
                        return -EFAULT;
                    }
                    uinsns += len;
                    free -= len;
                    if (!free) {
                        break;
                    }
                }
            } else {
                if (copy_to_user(uinsns, prog->bpf_func, ulen)) {
                    return -EFAULT;
                }
            }
        } else {
            info.jited_prog_insns = 0;
        }
    }

    ulen = info.nr_jited_ksyms;
    info.nr_jited_ksyms = prog->aux->func_cnt ?: 1;
    if (ulen) {
        if (bpf_dump_raw_ok(file->f_cred)) {
            unsigned long ksym_addr;
            u64 __user *user_ksyms;
            u32 i;

            /* copy the address of the kernel symbol
             * corresponding to each function
             */
            ulen = min_t(u32, info.nr_jited_ksyms, ulen);
            user_ksyms = u64_to_user_ptr(info.jited_ksyms);
            if (prog->aux->func_cnt) {
                for (i = 0; i < ulen; i++) {
                    ksym_addr = (unsigned long)prog->aux->func[i]->bpf_func;
                    if (put_user((u64)ksym_addr, &user_ksyms[i])) {
                        return -EFAULT;
                    }
                }
            } else {
                ksym_addr = (unsigned long)prog->bpf_func;
                if (put_user((u64)ksym_addr, &user_ksyms[0])) {
                    return -EFAULT;
                }
            }
        } else {
            info.jited_ksyms = 0;
        }
    }

    ulen = info.nr_jited_func_lens;
    info.nr_jited_func_lens = prog->aux->func_cnt ?: 1;
    if (ulen) {
        if (bpf_dump_raw_ok(file->f_cred)) {
            u32 __user *user_lens;
            u32 func_len, i;

            /* copy the JITed image lengths for each function */
            ulen = min_t(u32, info.nr_jited_func_lens, ulen);
            user_lens = u64_to_user_ptr(info.jited_func_lens);
            if (prog->aux->func_cnt) {
                for (i = 0; i < ulen; i++) {
                    func_len = prog->aux->func[i]->jited_len;
                    if (put_user(func_len, &user_lens[i])) {
                        return -EFAULT;
                    }
                }
            } else {
                func_len = prog->jited_len;
                if (put_user(func_len, &user_lens[0])) {
                    return -EFAULT;
                }
            }
        } else {
            info.jited_func_lens = 0;
        }
    }

    if (prog->aux->btf) {
        info.btf_id = btf_id(prog->aux->btf);
    }

    ulen = info.nr_func_info;
    info.nr_func_info = prog->aux->func_info_cnt;
    if (info.nr_func_info && ulen) {
        char __user *user_finfo;

        user_finfo = u64_to_user_ptr(info.func_info);
        ulen = min_t(u32, info.nr_func_info, ulen);
        if (copy_to_user(user_finfo, prog->aux->func_info, info.func_info_rec_size * ulen)) {
            return -EFAULT;
        }
    }

    ulen = info.nr_line_info;
    info.nr_line_info = prog->aux->nr_linfo;
    if (info.nr_line_info && ulen) {
        __u8 __user *user_linfo;

        user_linfo = u64_to_user_ptr(info.line_info);
        ulen = min_t(u32, info.nr_line_info, ulen);
        if (copy_to_user(user_linfo, prog->aux->linfo, info.line_info_rec_size * ulen)) {
            return -EFAULT;
        }
    }

    ulen = info.nr_jited_line_info;
    if (prog->aux->jited_linfo) {
        info.nr_jited_line_info = prog->aux->nr_linfo;
    } else {
        info.nr_jited_line_info = 0;
    }
    if (info.nr_jited_line_info && ulen) {
        if (bpf_dump_raw_ok(file->f_cred)) {
            __u64 __user *user_linfo;
            u32 i;

            user_linfo = u64_to_user_ptr(info.jited_line_info);
            ulen = min_t(u32, info.nr_jited_line_info, ulen);
            for (i = 0; i < ulen; i++) {
                if (put_user((__u64)(long)prog->aux->jited_linfo[i], &user_linfo[i])) {
                    return -EFAULT;
                }
            }
        } else {
            info.jited_line_info = 0;
        }
    }

    ulen = info.nr_prog_tags;
    info.nr_prog_tags = prog->aux->func_cnt ?: 1;
    if (ulen) {
        __u8 __user(*user_prog_tags)[BPF_TAG_SIZE];
        u32 i;

        user_prog_tags = u64_to_user_ptr(info.prog_tags);
        ulen = min_t(u32, info.nr_prog_tags, ulen);
        if (prog->aux->func_cnt) {
            for (i = 0; i < ulen; i++) {
                if (copy_to_user(user_prog_tags[i], prog->aux->func[i]->tag, BPF_TAG_SIZE)) {
                    return -EFAULT;
                }
            }
        } else {
            if (copy_to_user(user_prog_tags[0], prog->tag, BPF_TAG_SIZE)) {
                return -EFAULT;
            }
        }
    }

done:
    if (copy_to_user(uinfo, &info, info_len) || put_user(info_len, &uattr->info.info_len)) {
        return -EFAULT;
    }

    return 0;
}

static int bpf_map_get_info_by_fd(struct file *file, struct bpf_map *map, const union bpf_attr *attr,
                                  union bpf_attr __user *uattr)
{
    struct bpf_map_info __user *uinfo = u64_to_user_ptr(attr->info.info);
    struct bpf_map_info info;
    u32 info_len = attr->info.info_len;
    int err;

    err = bpf_check_uarg_tail_zero(uinfo, sizeof(info), info_len);
    if (err) {
        return err;
    }
    info_len = min_t(u32, sizeof(info), info_len);

    memset(&info, 0, sizeof(info));
    info.type = map->map_type;
    info.id = map->id;
    info.key_size = map->key_size;
    info.value_size = map->value_size;
    info.max_entries = map->max_entries;
    info.map_flags = map->map_flags;
    memcpy(info.name, map->name, sizeof(map->name));

    if (map->btf) {
        info.btf_id = btf_id(map->btf);
        info.btf_key_type_id = map->btf_key_type_id;
        info.btf_value_type_id = map->btf_value_type_id;
    }
    info.btf_vmlinux_value_type_id = map->btf_vmlinux_value_type_id;

    if (bpf_map_is_dev_bound(map)) {
        err = bpf_map_offload_info_fill(&info, map);
        if (err) {
            return err;
        }
    }

    if (copy_to_user(uinfo, &info, info_len) || put_user(info_len, &uattr->info.info_len)) {
        return -EFAULT;
    }

    return 0;
}

static int bpf_btf_get_info_by_fd(struct file *file, struct btf *btf, const union bpf_attr *attr,
                                  union bpf_attr __user *uattr)
{
    struct bpf_btf_info __user *uinfo = u64_to_user_ptr(attr->info.info);
    u32 info_len = attr->info.info_len;
    int err;

    err = bpf_check_uarg_tail_zero(uinfo, sizeof(*uinfo), info_len);
    if (err) {
        return err;
    }

    return btf_get_info_by_fd(btf, attr, uattr);
}

static int bpf_link_get_info_by_fd(struct file *file, struct bpf_link *link, const union bpf_attr *attr,
                                   union bpf_attr __user *uattr)
{
    struct bpf_link_info __user *uinfo = u64_to_user_ptr(attr->info.info);
    struct bpf_link_info info;
    u32 info_len = attr->info.info_len;
    int err;

    err = bpf_check_uarg_tail_zero(uinfo, sizeof(info), info_len);
    if (err) {
        return err;
    }
    info_len = min_t(u32, sizeof(info), info_len);

    memset(&info, 0, sizeof(info));
    if (copy_from_user(&info, uinfo, info_len)) {
        return -EFAULT;
    }

    info.type = link->type;
    info.id = link->id;
    info.prog_id = link->prog->aux->id;

    if (link->ops->fill_link_info) {
        err = link->ops->fill_link_info(link, &info);
        if (err) {
            return err;
        }
    }

    if (copy_to_user(uinfo, &info, info_len) || put_user(info_len, &uattr->info.info_len)) {
        return -EFAULT;
    }

    return 0;
}

#define BPF_OBJ_GET_INFO_BY_FD_LAST_FIELD info.info

static int bpf_obj_get_info_by_fd(const union bpf_attr *attr, union bpf_attr __user *uattr)
{
    int ufd = attr->info.bpf_fd;
    struct fd f;
    int err;

    if (CHECK_ATTR(BPF_OBJ_GET_INFO_BY_FD)) {
        return -EINVAL;
    }

    f = fdget(ufd);
    if (!f.file) {
        return -EBADFD;
    }

    if (f.file->f_op == &bpf_prog_fops) {
        err = bpf_prog_get_info_by_fd(f.file, f.file->private_data, attr, uattr);
    } else if (f.file->f_op == &bpf_map_fops) {
        err = bpf_map_get_info_by_fd(f.file, f.file->private_data, attr, uattr);
    } else if (f.file->f_op == &btf_fops) {
        err = bpf_btf_get_info_by_fd(f.file, f.file->private_data, attr, uattr);
    } else if (f.file->f_op == &bpf_link_fops) {
        err = bpf_link_get_info_by_fd(f.file, f.file->private_data, attr, uattr);
    } else {
        err = -EINVAL;
    }

    fdput(f);
    return err;
}

#define BPF_BTF_LOAD_LAST_FIELD btf_log_level

static int bpf_btf_load(const union bpf_attr *attr)
{
    if (CHECK_ATTR(BPF_BTF_LOAD)) {
        return -EINVAL;
    }

    if (!bpf_capable()) {
        return -EPERM;
    }

    return btf_new_fd(attr);
}

#define BPF_BTF_GET_FD_BY_ID_LAST_FIELD btf_id

static int bpf_btf_get_fd_by_id(const union bpf_attr *attr)
{
    if (CHECK_ATTR(BPF_BTF_GET_FD_BY_ID)) {
        return -EINVAL;
    }

    if (!capable(CAP_SYS_ADMIN)) {
        return -EPERM;
    }

    return btf_get_fd_by_id(attr->btf_id);
}

static int bpf_task_fd_query_copy(const union bpf_attr *attr, union bpf_attr __user *uattr, u32 prog_id, u32 fd_type,
                                  const char *buf, u64 probe_offset, u64 probe_addr)
{
    char __user *ubuf = u64_to_user_ptr(attr->task_fd_query.buf);
    u32 len = buf ? strlen(buf) : 0, input_len;
    int err = 0;

    if (put_user(len, &uattr->task_fd_query.buf_len)) {
        return -EFAULT;
    }
    input_len = attr->task_fd_query.buf_len;
    if (input_len && ubuf) {
        if (!len) {
            /* nothing to copy, just make ubuf NULL terminated */
            char zero = '\0';

            if (put_user(zero, ubuf)) {
                return -EFAULT;
            }
        } else if (input_len >= len + 1) {
            /* ubuf can hold the string with NULL terminator */
            if (copy_to_user(ubuf, buf, len + 1)) {
                return -EFAULT;
            }
        } else {
            /* ubuf cannot hold the string with NULL terminator,
             * do a partial copy with NULL terminator.
             */
            char zero = '\0';

            err = -ENOSPC;
            if (copy_to_user(ubuf, buf, input_len - 1)) {
                return -EFAULT;
            }
            if (put_user(zero, ubuf + input_len - 1)) {
                return -EFAULT;
            }
        }
    }

    if (put_user(prog_id, &uattr->task_fd_query.prog_id) || put_user(fd_type, &uattr->task_fd_query.fd_type) ||
        put_user(probe_offset, &uattr->task_fd_query.probe_offset) ||
        put_user(probe_addr, &uattr->task_fd_query.probe_addr)) {
        return -EFAULT;
    }

    return err;
}

#define BPF_TASK_FD_QUERY_LAST_FIELD task_fd_query.probe_addr

static int bpf_task_fd_query(const union bpf_attr *attr, union bpf_attr __user *uattr)
{
    pid_t pid = attr->task_fd_query.pid;
    u32 fd = attr->task_fd_query.fd;
    const struct perf_event *event;
    struct files_struct *files;
    struct task_struct *task;
    struct file *file;
    int err;

    if (CHECK_ATTR(BPF_TASK_FD_QUERY)) {
        return -EINVAL;
    }

    if (!capable(CAP_SYS_ADMIN)) {
        return -EPERM;
    }

    if (attr->task_fd_query.flags != 0) {
        return -EINVAL;
    }

    task = get_pid_task(find_vpid(pid), PIDTYPE_PID);
    if (!task) {
        return -ENOENT;
    }

    files = get_files_struct(task);
    put_task_struct(task);
    if (!files) {
        return -ENOENT;
    }

    err = 0;
    spin_lock(&files->file_lock);
    file = fcheck_files(files, fd);
    if (!file) {
        err = -EBADF;
    } else {
        get_file(file);
    }
    spin_unlock(&files->file_lock);
    put_files_struct(files);

    if (err) {
        goto out;
    }

    if (file->f_op == &bpf_link_fops) {
        struct bpf_link *link = file->private_data;

        if (link->ops == &bpf_raw_tp_link_lops) {
            struct bpf_raw_tp_link *raw_tp = container_of(link, struct bpf_raw_tp_link, link);
            struct bpf_raw_event_map *btp = raw_tp->btp;

            err = bpf_task_fd_query_copy(attr, uattr, raw_tp->link.prog->aux->id, BPF_FD_TYPE_RAW_TRACEPOINT,
                                         btp->tp->name, 0, 0);
            goto put_file;
        }
        goto out_not_supp;
    }

    event = perf_get_event(file);
    if (!IS_ERR(event)) {
        u64 probe_offset, probe_addr;
        u32 prog_id, fd_type;
        const char *buf;

        err = bpf_get_perf_event_info(event, &prog_id, &fd_type, &buf, &probe_offset, &probe_addr);
        if (!err) {
            err = bpf_task_fd_query_copy(attr, uattr, prog_id, fd_type, buf, probe_offset, probe_addr);
        }
        goto put_file;
    }

out_not_supp:
    err = -ENOTSUPP;
put_file:
    fput(file);
out:
    return err;
}

#define BPF_MAP_BATCH_LAST_FIELD batch.flags

#define BPF_DO_BATCH(fn)                                                                                               \
    do {                                                                                                               \
        if (!(fn)) {                                                                                                   \
            err = -ENOTSUPP;                                                                                           \
            goto err_put;                                                                                              \
        }                                                                                                              \
        err = fn(map, attr, uattr);                                                                                    \
    } while (0)

static int bpf_map_do_batch(const union bpf_attr *attr, union bpf_attr __user *uattr, int cmd)
{
    struct bpf_map *map;
    int err, ufd;
    struct fd f;

    if (CHECK_ATTR(BPF_MAP_BATCH)) {
        return -EINVAL;
    }

    ufd = attr->batch.map_fd;
    f = fdget(ufd);
    map = __bpf_map_get(f);
    if (IS_ERR(map)) {
        return PTR_ERR(map);
    }

    if ((cmd == BPF_MAP_LOOKUP_BATCH || cmd == BPF_MAP_LOOKUP_AND_DELETE_BATCH) &&
        !(map_get_sys_perms(map, f) & FMODE_CAN_READ)) {
        err = -EPERM;
        goto err_put;
    }

    if (cmd != BPF_MAP_LOOKUP_BATCH && !(map_get_sys_perms(map, f) & FMODE_CAN_WRITE)) {
        err = -EPERM;
        goto err_put;
    }

    if (cmd == BPF_MAP_LOOKUP_BATCH) {
        BPF_DO_BATCH(map->ops->map_lookup_batch);
    } else if (cmd == BPF_MAP_LOOKUP_AND_DELETE_BATCH) {
        BPF_DO_BATCH(map->ops->map_lookup_and_delete_batch);
    } else if (cmd == BPF_MAP_UPDATE_BATCH) {
        BPF_DO_BATCH(map->ops->map_update_batch);
    } else {
        BPF_DO_BATCH(map->ops->map_delete_batch);
    }

err_put:
    fdput(f);
    return err;
}

static int tracing_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
{
    if (attr->link_create.attach_type != prog->expected_attach_type) {
        return -EINVAL;
    }

    if (prog->expected_attach_type == BPF_TRACE_ITER) {
        return bpf_iter_link_attach(attr, prog);
    } else if (prog->type == BPF_PROG_TYPE_EXT) {
        return bpf_tracing_prog_attach(prog, attr->link_create.target_fd, attr->link_create.target_btf_id);
    }
    return -EINVAL;
}

#define BPF_LINK_CREATE_LAST_FIELD link_create.iter_info_len
static int link_create(union bpf_attr *attr)
{
    enum bpf_prog_type ptype;
    struct bpf_prog *prog;
    int ret;

    if (CHECK_ATTR(BPF_LINK_CREATE)) {
        return -EINVAL;
    }

    prog = bpf_prog_get(attr->link_create.prog_fd);
    if (IS_ERR(prog)) {
        return PTR_ERR(prog);
    }

    ret = bpf_prog_attach_check_attach_type(prog, attr->link_create.attach_type);
    if (ret) {
        goto out;
    }

    if (prog->type == BPF_PROG_TYPE_EXT) {
        ret = tracing_bpf_link_attach(attr, prog);
        goto out;
    }

    ptype = attach_type_to_prog_type(attr->link_create.attach_type);
    if (ptype == BPF_PROG_TYPE_UNSPEC || ptype != prog->type) {
        ret = -EINVAL;
        goto out;
    }

    switch (ptype) {
        case BPF_PROG_TYPE_CGROUP_SKB:
        case BPF_PROG_TYPE_CGROUP_SOCK:
        case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
        case BPF_PROG_TYPE_SOCK_OPS:
        case BPF_PROG_TYPE_CGROUP_DEVICE:
        case BPF_PROG_TYPE_CGROUP_SYSCTL:
        case BPF_PROG_TYPE_CGROUP_SOCKOPT:
            ret = cgroup_bpf_link_attach(attr, prog);
            break;
        case BPF_PROG_TYPE_TRACING:
            ret = tracing_bpf_link_attach(attr, prog);
            break;
        case BPF_PROG_TYPE_FLOW_DISSECTOR:
        case BPF_PROG_TYPE_SK_LOOKUP:
            ret = netns_bpf_link_create(attr, prog);
            break;
#ifdef CONFIG_NET
        case BPF_PROG_TYPE_XDP:
            ret = bpf_xdp_link_attach(attr, prog);
            break;
#endif
        default:
            ret = -EINVAL;
    }

out:
    if (ret < 0) {
        bpf_prog_put(prog);
    }
    return ret;
}

#define BPF_LINK_UPDATE_LAST_FIELD link_update.old_prog_fd

static int link_update(union bpf_attr *attr)
{
    struct bpf_prog *old_prog = NULL, *new_prog;
    struct bpf_link *link;
    u32 flags;
    int ret;

    if (CHECK_ATTR(BPF_LINK_UPDATE)) {
        return -EINVAL;
    }

    flags = attr->link_update.flags;
    if (flags & ~BPF_F_REPLACE) {
        return -EINVAL;
    }

    link = bpf_link_get_from_fd(attr->link_update.link_fd);
    if (IS_ERR(link)) {
        return PTR_ERR(link);
    }

    new_prog = bpf_prog_get(attr->link_update.new_prog_fd);
    if (IS_ERR(new_prog)) {
        ret = PTR_ERR(new_prog);
        goto out_put_link;
    }

    if (flags & BPF_F_REPLACE) {
        old_prog = bpf_prog_get(attr->link_update.old_prog_fd);
        if (IS_ERR(old_prog)) {
            ret = PTR_ERR(old_prog);
            old_prog = NULL;
            goto out_put_progs;
        }
    } else if (attr->link_update.old_prog_fd) {
        ret = -EINVAL;
        goto out_put_progs;
    }

    if (link->ops->update_prog) {
        ret = link->ops->update_prog(link, new_prog, old_prog);
    } else {
        ret = -EINVAL;
    }

out_put_progs:
    if (old_prog) {
        bpf_prog_put(old_prog);
    }
    if (ret) {
        bpf_prog_put(new_prog);
    }
out_put_link:
    bpf_link_put(link);
    return ret;
}

#define BPF_LINK_DETACH_LAST_FIELD link_detach.link_fd

static int link_detach(union bpf_attr *attr)
{
    struct bpf_link *link;
    int ret;

    if (CHECK_ATTR(BPF_LINK_DETACH)) {
        return -EINVAL;
    }

    link = bpf_link_get_from_fd(attr->link_detach.link_fd);
    if (IS_ERR(link)) {
        return PTR_ERR(link);
    }

    if (link->ops->detach) {
        ret = link->ops->detach(link);
    } else {
        ret = -EOPNOTSUPP;
    }

    bpf_link_put(link);
    return ret;
}

static struct bpf_link *bpf_link_inc_not_zero(struct bpf_link *link)
{
    return atomic64_fetch_add_unless(&link->refcnt, 1, 0) ? link : ERR_PTR(-ENOENT);
}

struct bpf_link *bpf_link_by_id(u32 id)
{
    struct bpf_link *link;

    if (!id) {
        return ERR_PTR(-ENOENT);
    }

    spin_lock_bh(&link_idr_lock);
    /* before link is "settled", ID is 0, pretend it doesn't exist yet */
    link = idr_find(&link_idr, id);
    if (link) {
        if (link->id) {
            link = bpf_link_inc_not_zero(link);
        } else {
            link = ERR_PTR(-EAGAIN);
        }
    } else {
        link = ERR_PTR(-ENOENT);
    }
    spin_unlock_bh(&link_idr_lock);
    return link;
}

#define BPF_LINK_GET_FD_BY_ID_LAST_FIELD link_id

static int bpf_link_get_fd_by_id(const union bpf_attr *attr)
{
    struct bpf_link *link;
    u32 id = attr->link_id;
    int fd;

    if (CHECK_ATTR(BPF_LINK_GET_FD_BY_ID)) {
        return -EINVAL;
    }

    if (!capable(CAP_SYS_ADMIN)) {
        return -EPERM;
    }

    link = bpf_link_by_id(id);
    if (IS_ERR(link)) {
        return PTR_ERR(link);
    }

    fd = bpf_link_new_fd(link);
    if (fd < 0) {
        bpf_link_put(link);
    }

    return fd;
}

DEFINE_MUTEX(bpf_stats_enabled_mutex);

static int bpf_stats_release(struct inode *inode, struct file *file)
{
    mutex_lock(&bpf_stats_enabled_mutex);
    static_key_slow_dec(&bpf_stats_enabled_key.key);
    mutex_unlock(&bpf_stats_enabled_mutex);
    return 0;
}

static const struct file_operations bpf_stats_fops = {
    .release = bpf_stats_release,
};

static int bpf_enable_runtime_stats(void)
{
    int fd;

    mutex_lock(&bpf_stats_enabled_mutex);

    /* Set a very high limit to avoid overflow */
    if (static_key_count(&bpf_stats_enabled_key.key) > INT_MAX / 0x2) {
        mutex_unlock(&bpf_stats_enabled_mutex);
        return -EBUSY;
    }

    fd = anon_inode_getfd("bpf-stats", &bpf_stats_fops, NULL, O_CLOEXEC);
    if (fd >= 0) {
        static_key_slow_inc(&bpf_stats_enabled_key.key);
    }

    mutex_unlock(&bpf_stats_enabled_mutex);
    return fd;
}

#define BPF_ENABLE_STATS_LAST_FIELD enable_stats.type

static int bpf_enable_stats(union bpf_attr *attr)
{
    if (CHECK_ATTR(BPF_ENABLE_STATS)) {
        return -EINVAL;
    }

    if (!capable(CAP_SYS_ADMIN)) {
        return -EPERM;
    }

    switch (attr->enable_stats.type) {
        case BPF_STATS_RUN_TIME:
            return bpf_enable_runtime_stats();
        default:
            break;
    }
    return -EINVAL;
}

#define BPF_ITER_CREATE_LAST_FIELD iter_create.flags

static int bpf_iter_create(union bpf_attr *attr)
{
    struct bpf_link *link;
    int err;

    if (CHECK_ATTR(BPF_ITER_CREATE)) {
        return -EINVAL;
    }

    if (attr->iter_create.flags) {
        return -EINVAL;
    }

    link = bpf_link_get_from_fd(attr->iter_create.link_fd);
    if (IS_ERR(link)) {
        return PTR_ERR(link);
    }

    err = bpf_iter_new_fd(link);
    bpf_link_put(link);

    return err;
}

#define BPF_PROG_BIND_MAP_LAST_FIELD prog_bind_map.flags

static int bpf_prog_bind_map(union bpf_attr *attr)
{
    struct bpf_prog *prog;
    struct bpf_map *map;
    struct bpf_map **used_maps_old, **used_maps_new;
    int i, ret = 0;

    if (CHECK_ATTR(BPF_PROG_BIND_MAP)) {
        return -EINVAL;
    }

    if (attr->prog_bind_map.flags) {
        return -EINVAL;
    }

    prog = bpf_prog_get(attr->prog_bind_map.prog_fd);
    if (IS_ERR(prog)) {
        return PTR_ERR(prog);
    }

    map = bpf_map_get(attr->prog_bind_map.map_fd);
    if (IS_ERR(map)) {
        ret = PTR_ERR(map);
        goto out_prog_put;
    }

    mutex_lock(&prog->aux->used_maps_mutex);

    used_maps_old = prog->aux->used_maps;

    for (i = 0; i < prog->aux->used_map_cnt; i++) {
        if (used_maps_old[i] == map) {
            bpf_map_put(map);
            goto out_unlock;
        }
    }

    used_maps_new = kmalloc_array(prog->aux->used_map_cnt + 1, sizeof(used_maps_new[0]), GFP_KERNEL);
    if (!used_maps_new) {
        ret = -ENOMEM;
        goto out_unlock;
    }

    memcpy(used_maps_new, used_maps_old, sizeof(used_maps_old[0]) * prog->aux->used_map_cnt);
    used_maps_new[prog->aux->used_map_cnt] = map;

    prog->aux->used_map_cnt++;
    prog->aux->used_maps = used_maps_new;

    kfree(used_maps_old);

out_unlock:
    mutex_unlock(&prog->aux->used_maps_mutex);

    if (ret) {
        bpf_map_put(map);
    }
out_prog_put:
    bpf_prog_put(prog);
    return ret;
}

SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, size)
{
    union bpf_attr attr;
    int err;

    if (sysctl_unprivileged_bpf_disabled && !bpf_capable()) {
        return -EPERM;
    }

    err = bpf_check_uarg_tail_zero(uattr, sizeof(attr), size);
    if (err) {
        return err;
    }
    size = min_t(u32, size, sizeof(attr));

    /* copy attributes from user space, may be less than sizeof(bpf_attr) */
    memset(&attr, 0, sizeof(attr));
    if (copy_from_user(&attr, uattr, size) != 0) {
        return -EFAULT;
    }

    err = security_bpf(cmd, &attr, size);
    if (err < 0) {
        return err;
    }

    switch (cmd) {
        case BPF_MAP_CREATE:
            err = map_create(&attr);
            break;
        case BPF_MAP_LOOKUP_ELEM:
            err = map_lookup_elem(&attr);
            break;
        case BPF_MAP_UPDATE_ELEM:
            err = map_update_elem(&attr);
            break;
        case BPF_MAP_DELETE_ELEM:
            err = map_delete_elem(&attr);
            break;
        case BPF_MAP_GET_NEXT_KEY:
            err = map_get_next_key(&attr);
            break;
        case BPF_MAP_FREEZE:
            err = map_freeze(&attr);
            break;
        case BPF_PROG_LOAD:
            err = bpf_prog_load(&attr, uattr);
            break;
        case BPF_OBJ_PIN:
            err = bpf_obj_pin(&attr);
            break;
        case BPF_OBJ_GET:
            err = bpf_obj_get(&attr);
            break;
        case BPF_PROG_ATTACH:
            err = bpf_prog_attach(&attr);
            break;
        case BPF_PROG_DETACH:
            err = bpf_prog_detach(&attr);
            break;
        case BPF_PROG_QUERY:
            err = bpf_prog_query(&attr, uattr);
            break;
        case BPF_PROG_TEST_RUN:
            err = bpf_prog_test_run(&attr, uattr);
            break;
        case BPF_PROG_GET_NEXT_ID:
            err = bpf_obj_get_next_id(&attr, uattr, &prog_idr, &prog_idr_lock);
            break;
        case BPF_MAP_GET_NEXT_ID:
            err = bpf_obj_get_next_id(&attr, uattr, &map_idr, &map_idr_lock);
            break;
        case BPF_BTF_GET_NEXT_ID:
            err = bpf_obj_get_next_id(&attr, uattr, &btf_idr, &btf_idr_lock);
            break;
        case BPF_PROG_GET_FD_BY_ID:
            err = bpf_prog_get_fd_by_id(&attr);
            break;
        case BPF_MAP_GET_FD_BY_ID:
            err = bpf_map_get_fd_by_id(&attr);
            break;
        case BPF_OBJ_GET_INFO_BY_FD:
            err = bpf_obj_get_info_by_fd(&attr, uattr);
            break;
        case BPF_RAW_TRACEPOINT_OPEN:
            err = bpf_raw_tracepoint_open(&attr);
            break;
        case BPF_BTF_LOAD:
            err = bpf_btf_load(&attr);
            break;
        case BPF_BTF_GET_FD_BY_ID:
            err = bpf_btf_get_fd_by_id(&attr);
            break;
        case BPF_TASK_FD_QUERY:
            err = bpf_task_fd_query(&attr, uattr);
            break;
        case BPF_MAP_LOOKUP_AND_DELETE_ELEM:
            err = map_lookup_and_delete_elem(&attr);
            break;
        case BPF_MAP_LOOKUP_BATCH:
            err = bpf_map_do_batch(&attr, uattr, BPF_MAP_LOOKUP_BATCH);
            break;
        case BPF_MAP_LOOKUP_AND_DELETE_BATCH:
            err = bpf_map_do_batch(&attr, uattr, BPF_MAP_LOOKUP_AND_DELETE_BATCH);
            break;
        case BPF_MAP_UPDATE_BATCH:
            err = bpf_map_do_batch(&attr, uattr, BPF_MAP_UPDATE_BATCH);
            break;
        case BPF_MAP_DELETE_BATCH:
            err = bpf_map_do_batch(&attr, uattr, BPF_MAP_DELETE_BATCH);
            break;
        case BPF_LINK_CREATE:
            err = link_create(&attr);
            break;
        case BPF_LINK_UPDATE:
            err = link_update(&attr);
            break;
        case BPF_LINK_GET_FD_BY_ID:
            err = bpf_link_get_fd_by_id(&attr);
            break;
        case BPF_LINK_GET_NEXT_ID:
            err = bpf_obj_get_next_id(&attr, uattr, &link_idr, &link_idr_lock);
            break;
        case BPF_ENABLE_STATS:
            err = bpf_enable_stats(&attr);
            break;
        case BPF_ITER_CREATE:
            err = bpf_iter_create(&attr);
            break;
        case BPF_LINK_DETACH:
            err = link_detach(&attr);
            break;
        case BPF_PROG_BIND_MAP:
            err = bpf_prog_bind_map(&attr);
            break;
        default:
            err = -EINVAL;
            break;
    }

    return err;
}
